A color-coated plate production line VOCs recovery treatment device and treatment method

Abstract

This invention discloses a VOCs recovery and treatment device and method for a color-coated steel sheet production line, relating to the field of waste gas treatment technology in color-coated steel sheet production. The VOCs recovery and treatment device for the color-coated steel sheet production line includes a shell, within which an adsorption assembly is rotatably installed. A second partition is also provided within the shell, and a first partition is symmetrically installed within the shell. The first and second partitions divide the internal space of the shell into an adsorption zone, a desorption zone, and a cooling zone. Activated carbon plates periodically circulate within the adsorption, desorption, and cooling zones, achieving automated circulation of the entire adsorption, desorption, and cooling process. Compared to traditional fixed-bed systems that require shutdown for regeneration, this significantly improves system throughput efficiency. The arrangement of the first and second partitions, combined with the first and second arc-shaped plates, creates strict temperature zone separation, ensuring that ambient temperature adsorption in the adsorption zone, high-temperature desorption in the desorption zone, and cryogenic regeneration in the cooling zone do not interfere with each other, avoiding cross-heat loss and guaranteeing the processing efficiency of each stage.

Description

Technical Field

[0001] This invention relates to the field of waste gas treatment technology in color-coated steel sheet production, specifically to a VOCs recovery and treatment device and method for color-coated steel sheet production lines. Background Technology

[0002] In the field of color-coated steel sheet production, with the accelerated advancement of industrial modernization, product applications have widely covered numerous industries such as construction, home appliances, and automobiles. However, the volatile organic compounds (VOCs) emitted from coatings, solvents, and diluents during the coating and drying processes pose a significant environmental challenge. These VOCs, once released into the atmosphere, become core precursors to photochemical smog, reacting with nitrogen oxides under sunlight to generate secondary pollutants such as ozone and peroxyacetyl nitrate, significantly damaging air quality, reducing atmospheric visibility, and causing chain-reaction damage to ecosystems. Halogenated hydrocarbons, in particular, directly erode the ozone layer, exacerbating global warming. Current mainstream treatment technologies suffer from systemic defects: while direct combustion can achieve harmless transformation, its reliance on continuous high-temperature combustion leads to excessively high energy consumption, deviating from the principles of sustainable development and failing to recover valuable components; adsorption methods are limited by the insufficient efficiency of traditional adsorbents, limiting their effectiveness in treating low-concentration, high-volume conditions, and the difficulty in adsorbent regeneration leads to frequent replacements, increasing costs and generating large amounts of secondary polluting solid waste; absorption methods, due to their narrow absorbent selectivity, complex wastewater treatment, and high equipment investment, place a heavy burden on small and medium-sized enterprises.

[0003] Chinese patent CN119869142A discloses a VOC recovery and treatment device for the production process of color-coated steel sheets. This device adopts an innovative process combining condensation and adsorption. In the initial stage of waste gas treatment, a condenser converts some easily condensable VOCs into liquid for recovery, effectively reducing the load on subsequent adsorption treatment. Activated carbon fiber is used as an adsorbent, which has a large specific surface area and abundant microporous structure, exhibiting extremely high adsorption efficiency and adsorption capacity for the remaining VOCs. It can almost completely capture VOCs in the waste gas. The recovered VOCs can be reprocessed or sold as resources, significantly improving resource utilization, reducing resource waste, and bringing additional economic benefits to enterprises.

[0004] However, it still exposes significant bottlenecks in practical applications. Traditional devices are difficult to operate continuously, and shutdown is still required during the regeneration stage. After adsorption saturation, the airflow needs to be interrupted for thermal desorption, resulting in a serious mismatch between the system's throughput capacity and the large-volume continuous production of color coating lines. Especially when facing the large volume of exhaust gas emitted from the drying oven production line, which is tens of meters long, frequent start-ups and shutdowns cause a precipitous drop in treatment efficiency, creating a discontinuity in the process. Secondly, the problem of adsorption kinetic failure for low-concentration exhaust gas is prominent. Traditional fixed-bed adsorption structures are extremely unsuitable for large-volume, low-concentration operating conditions: when the VOC concentration of the exhaust gas is below the critical value, the activated carbon fiber bed exhibits a significant edge penetration effect, and the airflow forms a preferential channel in the static adsorbent, causing a large amount of exhaust gas to escape without being fully adsorbed, resulting in the actual purification efficiency being far lower than the measured value. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a VOCs recovery and treatment device and method for color-coated steel sheet production lines, solving the problems raised in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a VOCs recovery and treatment device for a color-coated steel sheet production line, comprising a housing, an adsorption assembly rotatably mounted inside the housing, and a second partition plate inside the housing. A first partition plate is also symmetrically mounted inside the housing. The first and second partition plates divide the internal space of the housing into an adsorption zone, a desorption zone, and a cooling zone. The adsorption assembly includes a rotating frame rotatably mounted inside the housing, with a partition plate inside the rotating frame, and an activated carbon layer installed between adjacent partition plates. The cooling zone contains a waste gas condensation assembly for condensing waste gas during input and cooling the adsorption assembly after desorption. The adsorption zone contains a gas-liquid separation assembly to allow the cooled waste gas to be input into the adsorption zone for adsorption treatment. The desorption zone contains a microwave heating element for desorption after adsorption by the activated carbon layer.

[0007] Furthermore, the exhaust gas condensation assembly includes a condensation chamber located within the cooling zone. A liquid nitrogen input pipe is installed on the outside of the condensation chamber, and a condensation pipe is installed inside the condensation chamber. The output end of the condensation pipe is connected to the gas-liquid separation assembly, and an exhaust gas input pipe is installed on the input end of the condensation pipe.

[0008] Furthermore, a hollow bushing is installed in the middle of the outer shell, and a vent hole is provided at the upper outer side of the hollow bushing. The condensation chamber is connected to the cooling zone, so that after the liquid nitrogen is vaporized, it travels upward along the outer shell axis and enters the interior of the hollow bushing through the vent hole.

[0009] Furthermore, a first arc-shaped plate is fixed inside the outer shell on the outside of the adsorption zone, and a second arc-shaped plate is fixed inside the outer shell on the outside of the desorption zone. Both the first and second arc-shaped plates are provided with through slots, which are rotatably connected to the rotating frame.

[0010] Furthermore, the gas-liquid separation assembly includes a gas-liquid separation tube fixed inside the outer shell, a liquid accumulation chamber at the lower end of the gas-liquid separation tube, a connecting pipe connected to the adsorption zone fixed at the upper outer end of the gas-liquid separation tube, a spiral plate fixed inside the gas-liquid separation tube, and a gas-liquid input pipe installed at the output end of the condenser tube. The gas-liquid input pipe inputs the waste gas tangentially into the gas-liquid separation tube.

[0011] Furthermore, the microwave heating element includes a microwave generator fixed inside the housing, and the microwave generator is provided with a heating plate for heating the activated carbon layer so that the waste gas adsorbed on the activated carbon layer is desorbed at high temperature; a vacuum pump is fixed at the bottom inside the housing, the input end of the vacuum pump is equipped with a manifold communicating with the desorption zone, and the output end of the vacuum pump is equipped with a concentrated waste gas output pipe.

[0012] Furthermore, the adsorption assembly also includes: an inner liner, which is fixedly connected to one end of the isolation plate; a bottom mesh plate, fixed to the bottom of the inner liner; and a top mesh plate, installed between two adjacent isolation plates and located at the top of the activated carbon layer.

[0013] Furthermore, a driven shaft is rotatably mounted in the cooling zone, a pinion is fixed to the outside of the driven shaft, and a groove is provided in the middle of the outer side of the rotating frame, with an external gear meshing with the pinion fixed in the groove.

[0014] Furthermore, a motor is fixed to the upper outer side of the outer shell, the output end of the motor extends into the hollow bushing and is equipped with an exhaust fan, and a drive wheel is also fixed to the output end of the motor. The upper end of the driven shaft passes through the upper outer side of the outer shell and is fixed with a driven wheel. A synchronous transmission belt is provided between the driven wheel and the drive wheel.

[0015] In addition, the present invention also provides a method for VOCs recovery and treatment in a color-coated steel sheet production line, which uses the aforementioned VOCs recovery and treatment device for a color-coated steel sheet production line, and specifically includes the following steps:

[0016] S1. Collect and filter workshop exhaust gas;

[0017] S2. The exhaust gas enters the exhaust gas condensation component through the exhaust gas inlet pipe to cool and liquefy, forming a gas-liquid mixture;

[0018] S3. The gas-liquid mixture is fed into the gas-liquid separation component for separation, the liquid phase is recovered, and the gas phase is fed into the adsorption zone for adsorption by the adsorption component.

[0019] S4. The saturated adsorption component is transferred to the desorption zone, the microwave heating element heats the desorption, and the vacuum pump draws the desorbed waste gas.

[0020] S5. The exhaust fan draws nitrogen into the hollow bushing, and the adsorption components in the cooling zone exchange heat with the nitrogen to achieve regeneration.

[0021] The present invention has the following beneficial effects:

[0022] (1) The VOCs recovery and treatment device and treatment method of the color-coated plate production line, the rotating frame drives the activated carbon plate to periodically rotate in the adsorption zone, desorption zone and cooling zone through the meshing transmission of the external gear and the small gear, realizing the full-process automated cycle of adsorption, desorption and cooling. Compared with the traditional fixed bed that requires shutdown for regeneration, this design breaks through the problem of continuous treatment under large air volume conditions, significantly improving the system throughput efficiency. Through the setting of the first partition and the second partition, combined with the first arc plate and the second arc plate, a strict temperature zone separation is formed to ensure that the adsorption zone at room temperature, the desorption zone at high temperature, and the cooling zone at deep cryogenic regeneration do not interfere with each other, avoid cross-loss of heat energy, and ensure the treatment efficiency of each link.

[0023] (2) The VOCs recovery and treatment device and treatment method of the color-coated plate production line utilizes liquid nitrogen input pipe to inject into the condensing chamber and vaporize and absorb heat to form an ultra-low temperature environment in the condensing tube to liquefy high-boiling-point VOCs, thereby reducing the adsorption burden of the activated carbon plate in the adsorption zone. The vaporized nitrogen rises along the outer shell axis to pre-cool and regenerate the activated carbon plate that has entered the cooling zone, realizing the phased utilization of liquid nitrogen cold energy, which not only improves the condensation efficiency but also accelerates the cooling of the carbon layer and reduces thermal stress damage.

[0024] (3) The VOCs recovery and treatment device and treatment method of the color-coated plate production line are tangentially input into the gas-liquid separation pipe through the gas-liquid input pipe. Under the guidance of the spiral plate, a high-speed swirling flow field is formed. The liquid phase is thrown to the pipe wall by centrifugal force. After being guided by the conical panel, it is recovered by the condensate waste liquid output pipe. The inclined pipe and the "gas lock" structure prevent the gas phase from escaping. The activated carbon plate adopts a multi-layer configuration. The micropores preferentially adsorb non-polar VOCs such as benzene series, while the mesopores retain ester macromolecules, thereby improving the adsorption capacity and selectivity. The support system composed of the bottom mesh plate and the detachable top mesh plate facilitates the replacement and maintenance of the activated carbon plate.

[0025] (4) The VOCs recovery and treatment device and treatment method of the color-coated plate production line: the microwave generator releases microwave energy through the silicon carbide heating plate to stimulate the polar VOC molecules to generate heat through friction. The vacuum pump maintains the low pressure environment in the desorption zone, which significantly reduces the boiling point of VOCs. The two work together to achieve low-temperature deep desorption and avoid high-temperature oxidation damage to activated carbon.

[0026] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention;

[0028] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0029] Figure 3 In this invention Figure 2 Another perspective view;

[0030] Figure 4 This is a schematic diagram of the structure of the waste gas condensation component in this invention;

[0031] Figure 5 This is a schematic diagram of the internal structure of the gas-liquid separation component in this invention;

[0032] Figure 6 This is a schematic diagram of the installation structure of the first partition and the second partition in this invention;

[0033] Figure 7 This is a schematic diagram of the installation structure of the microwave heating element in this invention;

[0034] Figure 8 This is a schematic diagram of the internal structure of the adsorption component in this invention;

[0035] Figure 9 This is a schematic diagram of the mounting structure of the external gear in this invention;

[0036] Figure 10 In this invention Figure 9 Top view.

[0037] In the diagram: 1. Outer casing; 2. Inspection door; 3. Purified exhaust gas pipe; 4. Condensed waste liquid output pipe; 5. Liquid nitrogen input pipe; 6. Concentrated waste gas output pipe; 7. Waste gas input pipe; 8. Motor; 9. Drive wheel; 10. Synchronous drive belt; 11. Driven wheel; 12. Driven shaft; 13. Pinion gear; 14. Vacuum pump; 15. Condensation chamber; 16. Condensation pipe; 17. First partition; 18. Second partition; 19. Gas-liquid separation pipe; 20. 21. First arc-shaped plate; 22. Second arc-shaped plate; 23. Microwave generator; 24. Rotating frame; 25. External gear; 26. Vent hole; 27. Manifold; 28. Spiral plate; 29. ​​Hollow bushing; 30. Gas-liquid input pipe; 31. Through groove; 32. Heating plate; 33. Exhaust fan; 34. Nitrogen output pipe; 35. Bottom mesh plate; 36. Activated carbon layer; 37. Lining; 38. Top mesh plate; 39. Isolation plate; 30. Connecting pipe. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0040] The following is based on Figures 1-10 This invention describes the VOCs recovery and treatment device and method for color-coated steel sheet production lines provided in embodiments of the present invention.

[0041] Please see Figures 1-10 This invention provides a technical solution: a VOCs recovery and treatment device for a color-coated steel sheet production line, comprising a housing 1, an adsorption assembly rotatably installed inside the housing 1, a second partition 18 inside the housing 1, and a first partition 17 symmetrically installed inside the housing 1. The first partition 17 and the second partition 18 divide the internal space of the housing 1 into an adsorption zone, a desorption zone, and a cooling zone. It should be noted that a purified exhaust pipe 3 is provided at the bottom of the adsorption zone to facilitate the discharge of the adsorbed exhaust gas. The first partition 17 and the second partition 18 are both made of heat-insulating material to avoid heat exchange between the adsorption zone, the desorption zone, and the cooling zone. An inspection door 2 is hinged on the outside of the housing 1 at the location of the cooling zone for the inspection and maintenance of the internal components of the housing 1. A reflective aluminum foil layer can be added inside the first partition 17 and the second partition 18 to enhance heat radiation blocking. The inspection door 2 can be equipped with a safety interlock switch to automatically cut off the power when the door is opened.

[0042] The adsorption assembly includes a rotating frame 23 rotatably mounted inside the housing 1. The rotating frame 23 contains isolation plates 38, and activated carbon layers 35 are installed between adjacent sets of isolation plates 38 for the adsorption treatment of VOCs waste gas. The rotating frame 23 separates multiple activated carbon layers 35 through the isolation plates 38, realizing a modular adsorption unit. A waste gas condensation assembly is provided in the cooling zone for condensing the waste gas during input and cooling the adsorption assembly after desorption, causing the higher boiling point VOCs in the waste gas to change from a gaseous state to a liquid state. The activated carbon layers 35 are pre-cooled by the upward flow of gaseous nitrogen, thus regenerating the activated carbon layers 35. A gas-liquid separation assembly is provided in the adsorption zone to separate the gas and liquid phases and allow the cooled waste gas to be input into the adsorption unit. The adsorption zone is equipped with a microwave heating element for desorption after adsorption by the activated carbon plate 35. The adsorption zone is maintained at room temperature to achieve VOCs adsorption, the desorption zone is at high temperature for microwave desorption, and the cooling zone is at low temperature for nitrogen regeneration. The zoned design ensures that the temperature of each stage does not interfere with each other. After the activated carbon is saturated, it is automatically transferred to the desorption zone, and a new carbon layer enters the adsorption zone at the same time, which solves the problem of regeneration during shutdown in traditional fixed beds. The activated carbon plate 35 is preferably a multi-layer structure. The multi-layer structure preferentially adsorbs non-polar benzene compounds through micropore capillary action, and retains large molecular esters in the mesopores to improve the adsorption capacity. The rotating frame 23 rotates periodically, so that the activated carbon plate 35 goes through the cycle path of adsorption, desorption and cooling in sequence to achieve continuous treatment.

[0043] like Figure 2 , Figure 4 and Figure 6 As shown, the exhaust gas condensation assembly provided in this embodiment includes a condensation chamber 15 located in the cooling zone. A liquid nitrogen input pipe 5 is installed on the outside of the condensation chamber 15, and a condensation pipe 16 is provided inside the condensation chamber 15. The output end of the condensation pipe 16 is connected to the gas-liquid separation assembly, and an exhaust gas input pipe 7 is installed on the input end of the condensation pipe 16. The input exhaust gas is condensed by the input liquid nitrogen, thereby changing the high-boiling-point VOCs in the exhaust gas from a gaseous state to a liquid state, so as to reduce the adsorption burden of the subsequent adsorption assembly. The liquid nitrogen vaporization absorbs heat to achieve a -196℃ cryogenic environment, efficiently liquefying high-boiling-point VOCs. The vaporized nitrogen rises to pre-cool the regenerated carbon layer, reducing thermal stress damage.

[0044] Liquid nitrogen is injected into the condensation chamber 15 through the liquid nitrogen input pipe 5. The vaporization and heat absorption cause the temperature of the exhaust gas in the condensation pipe 16 to drop sharply, and high-boiling-point VOCs are liquefied and released. The vaporized nitrogen rises naturally and pre-cools and regenerates the activated carbon layer 35 in the cooling zone. The nitrogen enters the hollow bushing 28 through the vent 25 and is recovered through the nitrogen output pipe 33. The liquid nitrogen phase change cooling energy is first used for exhaust gas condensation and then for carbon layer cooling to achieve energy closed loop. The vaporized nitrogen has a low density and rises along the axial direction of the outer shell 1 under the action of air pressure without additional power, which is energy-saving and efficient.

[0045] like Figure 2 , Figure 4 , Figure 6 and Figure 7 As shown, to prevent the liquid nitrogen from being lost after vaporization, a hollow bushing 28 is installed in the middle of the outer shell 1. A vent hole 25 is provided at the upper outer end of the hollow bushing 28, and a nitrogen output pipe 33 is provided at the lower end of the hollow bushing 28 to facilitate the recovery of nitrogen. The recovered nitrogen has a high heat energy content, which can be replaced and utilized by a heat exchanger, thereby improving the energy utilization efficiency. The condensation chamber 15 is connected to the cooling zone, so that after the liquid nitrogen is vaporized, it rises along the axial direction of the outer shell 1 and enters the interior of the hollow bushing 28 through the vent hole 25. The gaseous nitrogen rises and pre-cools the activated carbon plate 35, thereby realizing the regeneration of the activated carbon plate 35.

[0046] like Figure 4 , Figure 5 and Figure 7 As shown, in order to achieve relative spatial independence during adsorption and desorption of the adsorption component and to ensure heat flow, a first arc-shaped plate 20 is fixed inside the outer shell 1 outside the adsorption zone, and a second arc-shaped plate 21 is fixed inside the outer shell 1 outside the desorption zone. The first arc-shaped plate 20 and the second arc-shaped plate 21 form a "C" shape structure. Both the first arc-shaped plate 20 and the second arc-shaped plate 21 are provided with through grooves 30, which are rotatably connected to the rotating frame 23 to support the adsorption component and ensure its stability.

[0047] like Figure 4 , Figure 5 and Figure 7 As shown, to achieve gas-liquid separation after condensation of waste gas, the gas-liquid separation assembly provided in this embodiment includes a gas-liquid separation pipe 19 fixed inside the outer shell 1. An insulation layer is provided inside the gas-liquid separation pipe 19 to prevent the condensed waste liquid from vaporizing due to heat and to ensure a lower temperature of the waste gas, which is beneficial for subsequent adsorption. A liquid accumulation chamber is provided at the lower end of the gas-liquid separation pipe 19. A connecting pipe 39 communicating with the adsorption zone is fixed at the upper outer end of the gas-liquid separation pipe 19. The connecting pipe 39 inputs the cooled waste gas to the top of the adsorption zone. A spiral plate 27 is fixed inside the gas-liquid separation pipe 19. A gas-liquid input pipe 29 is installed at the output end of the condenser pipe 16, and the gas-liquid input pipe 29 inputs the waste gas tangentially along the gas-liquid separation pipe 19 into the interior of the gas-liquid separation pipe 19. By tangentially inputting the gas-liquid mixture along the gas-liquid separation pipe 19, the waste gas spirals upward under the action of the spiral plate 27. Under the action of centrifugal force, the liquid phase is thrown against the inner wall of the gas-liquid separation pipe 19. Under the action of gravity, the liquid phase flows downward along the inner wall of the gas-liquid separation pipe 19. To prevent the gas from escaping from the lower end of the gas-liquid separation pipe 19, the gas-liquid input pipe 29 is tilted towards the upper end of the gas-liquid separation pipe 19. A conical panel is installed below the output end of the gas-liquid separation pipe 29. A water inlet is provided on the side of the conical panel to facilitate the deflection of the airflow and allow the liquid phase to enter the lower end of the gas-liquid separation pipe 19 along the water inlet. A condensate waste liquid output pipe 4 is provided at the lower end of the gas-liquid separation pipe 19 to facilitate the collection of waste liquid.

[0048] It should be noted that the tangential air intake forms a swirling flow field under the guidance of the spiral plate 27, and achieves gas-liquid stratification through centrifugal force. The conical panel forces the airflow to turn, and the droplets converge and flow downwards due to inertia when they collide with the wall. The inclined gas-liquid input pipe 29 and the conical panel combine to form an "airlock" structure, which blocks the gas from escaping from the liquid accumulation chamber. The inner wall of the gas-liquid separation pipe 19 can be provided with vertical guide strips, and its inner wall can be coated with polytetrafluoroethylene to reduce droplet adhesion. An ultrasonic transducer can be installed at the bottom of the liquid accumulation chamber to prevent the accumulation of high-viscosity resin.

[0049] like Figure 2 and Figure 7 As shown, to achieve the desorption of adsorbed waste gas in the adsorption component, the microwave heating element provided in this embodiment includes a microwave generator 22 fixed inside the outer shell 1. The microwave generator 22 is provided with a heating plate 31 for heating the activated carbon layer 35. Microwaves penetrate the carbon layer to excite polar VOC molecules (such as ketones) to rotate at high speed and generate heat through friction, thereby achieving selective heating. Waveguide directional radiation ensures that energy is focused on the carbon layer. The heating plate 31 is made of silicon carbide to improve microwave absorption efficiency, so that the waste gas adsorbed on the activated carbon layer 35 is desorbed at high temperature. A vacuum pump 14 is fixed at the bottom inside the outer shell 1. The input end of the vacuum pump 14 is equipped with a manifold 26 that communicates with the desorption zone, and the output end of the vacuum pump 14 is equipped with a concentrated waste gas output pipe 6. The vacuum environment reduces the boiling point of VOCs and reduces desorption energy consumption.

[0050] like Figures 8-10 As shown, the adsorption assembly provided in this embodiment also includes an inner liner 36, a bottom mesh plate 34, and a top mesh plate 37. The inner liner 36 is fixedly connected to one end of the isolation plate 38. The bottom mesh plate 34 is fixed to the bottom of the inner liner 36 for supporting the activated carbon layer 35. The top mesh plate 37 is installed between two adjacent isolation plates 38 and is located on the upper end of the activated carbon layer 35. The top mesh plate 37 can be optionally snap-fitted to the isolation plate 38 to facilitate replacement and maintenance of the activated carbon layer 35 after long-term use.

[0051] The inner liner 36 is fixedly connected to the isolation plate 38, forming the supporting skeleton of the activated carbon layer 35. The bottom mesh plate 34 and the detachable top mesh plate 37 provide bottom support and top pressing respectively, ensuring that the carbon layer is evenly distributed and achieving re-filtration during the adsorption of waste gas. The top mesh plate 37 can be quickly disassembled, making it easy to replace the activated carbon layer 35.

[0052] like Figures 1-7As shown, in order to achieve the rotation of the adsorption component, a driven shaft 12 is rotatably installed in the cooling zone. A small gear 13 is fixed on the outside of the driven shaft 12. A groove is provided in the middle of the outer side of the rotating frame 23. An external gear 24 that meshes with the small gear 13 is fixed in the groove. The small gear 13 drives the external gear 24 to ensure that the rotating frame 23 rotates smoothly at low speed to match the adsorption, desorption and regeneration cycle requirements of the activated carbon plate 35.

[0053] like Figures 1-7 As shown, to improve the nitrogen suction effect, a motor 8 is fixed at the upper outer side of the outer shell 1. The output end of the motor 8 extends into the hollow bushing 28 and is equipped with an exhaust fan 32. The exhaust fan 32 increases the nitrogen flow rate and accelerates the cooling and regeneration of the activated carbon shelf 35. The output end of the motor 8 is also fixed with a drive wheel 9. The upper end of the driven shaft 12 passes through the upper outer side of the outer shell 1 and is fixed with a driven wheel 11. A synchronous transmission belt 10 is provided between the driven wheel 11 and the drive wheel 9. The exhaust fan 32 drives the nitrogen to flow inside the cooling zone, so as to form an inert cooling atmosphere, thereby improving the cooling and regeneration effect of the activated carbon shelf 35.

[0054] During use (operation), the adsorption zone, desorption zone, and cooling zone are divided by the first partition 17 and the second partition 18. The waste gas enters the condensation chamber 15 of the cooling zone through the waste gas inlet pipe 7 and is diverted through the condenser pipe 16. Liquid nitrogen is injected through the liquid nitrogen inlet pipe 5 and vaporizes and absorbs heat, which cools the condenser pipe 16 and further liquefies the high-boiling-point VOCs. The gas-liquid mixture enters the gas-liquid separation pipe 19 tangentially through the gas-liquid inlet pipe 29. Under the guidance of the spiral plate 27, a swirling flow field is formed. The liquid phase is thrown against the wall of the gas-liquid separation pipe 19 by centrifugal force and is recovered by the condensate waste liquid outlet pipe 4 after being guided by the conical panel. The gas phase enters the adsorption zone through the connecting pipe 39.

[0055] Within the adsorption zone, the rotating frame 23 drives the activated carbon plate 35 to rotate periodically. The multi-layer activated carbon structure preferentially adsorbs benzene compounds through micropore capillary action and retains esters through mesopores, thereby capturing gaseous VOCs. After saturation, the activated carbon plate 35 moves into the desorption zone. At this time, the microwave generator 22 releases microwaves through the silicon carbide heating plate 31 to excite polar VOC molecules to generate heat through friction. At the same time, the vacuum pump 14 maintains a low-pressure environment to lower the boiling point, promoting the desorption of VOCs and output through the manifold 26.

[0056] After desorption, the activated carbon plate 35 enters the cooling zone for regeneration. Low-temperature nitrogen gas generated by the vaporization of liquid nitrogen rises along the cooling zone, pre-cooling the activated carbon plate 35. The nitrogen gas enters the hollow bushing 28 through the vent 25 and is ultimately guided by the nitrogen output pipe 33 to an external heat exchanger to recover the cold energy. During this process, the motor 8 drives the drive wheel 9, which in turn drives the driven wheel 11 via the synchronous transmission belt 10. This causes the pinion 13 on the driven shaft 12 to mesh with the external gear 24, achieving a low-speed, stable rotation of the rotating frame 23 to match the adsorption... The desorption and cooling cycle is met by driving the exhaust fan 32 to rotate via the motor 8, which accelerates the entry of nitrogen into the hollow bushing 28 in the cooling zone, thereby improving nitrogen recovery efficiency. The activated carbon layer 35 is supported by the inner lining 36, the bottom mesh plate 34, and the detachable top mesh plate 37, which facilitates maintenance and replacement. The entire process achieves efficient VOCs recovery and activated carbon regeneration through the synergistic effects of physical phase change, centrifugal separation, microwave selective heating, and inert gas circulation, with no risk of secondary pollution, significantly improving system energy efficiency and stability.

[0057] The exhaust gas enters the condensation chamber 15 through the exhaust gas inlet pipe 7. High-boiling-point VOCs are liquefied by deep cryogenic cooling with liquid nitrogen. The gas-liquid mixture is centrifuged and separated in the gas-liquid separation pipe 15. The liquid phase is recovered and the gas phase is purified by adsorption. The saturated activated carbon plate 35 is transferred to the desorption zone and desorbed by microwave vacuum. After regeneration, the activated carbon plate 35 is pre-cooled by nitrogen in the cooling zone to complete the cycle. There are no chemical additives throughout the process, realizing the resource recovery of VOCs. The activated carbon plate 35 is regenerated in situ. This rotary adsorption structure enables continuous treatment of large air volume, and the reuse of liquid nitrogen cooling energy reduces the total energy consumption of the system.

[0058] In addition, the present invention also provides a method for VOCs recovery and treatment in a color-coated steel sheet production line, which uses the VOCs recovery and treatment device for a color-coated steel sheet production line provided in this embodiment, and specifically includes the following steps:

[0059] S1. Collect and filter the workshop exhaust gas to remove particulate impurities;

[0060] S2. The exhaust gas enters the exhaust gas condensation component through the exhaust gas inlet pipe 7 to cool and liquefy, forming a gas-liquid mixture. The liquid nitrogen phase change cold energy is utilized in stages. The exhaust gas is condensed first and then the activated carbon plate 35 is pre-cooled to regenerate the activated carbon plate 35.

[0061] S3. The gas-liquid mixture is input to the gas-liquid separation component for separation, the liquid phase is recovered, and the gas phase is input to the adsorption zone for adsorption by the adsorption component. The gas-liquid separation tube 19 is designed to maintain a low temperature and enhance the adsorption efficiency of the activated carbon plate 35.

[0062] S4. The saturated adsorption component is transferred to the desorption zone, the microwave heating element heats the desorption, and the vacuum pump 14 draws the desorbed waste gas to achieve low-temperature deep desorption and avoid damage to the activated carbon plate 35.

[0063] S5, the exhaust fan 32 draws nitrogen into the hollow bushing 28, and the adsorption component in the cooling zone exchanges heat with the nitrogen to achieve regeneration.

[0064] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0065] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A VOCs recovery and treatment device for a color-coated steel sheet production line, comprising a housing (1), characterized in that: An adsorption assembly is rotatably installed inside the outer shell (1), and a second partition (18) is provided inside the outer shell (1). A first partition (17) is also symmetrically installed inside the outer shell (1). The first partition (17) and the second partition (18) divide the internal space of the outer shell (1) into an adsorption zone, a desorption zone, and a cooling zone, wherein: The adsorption assembly includes a rotating frame (23) rotatably mounted inside the housing (1), with a partition plate (38) inside the rotating frame (23), and an activated carbon layer (35) installed between two adjacent partition plates (38). The cooling zone is equipped with a waste gas condensation component, which is used to condense the waste gas when it is input and to cool down the adsorption component after desorption. The adsorption zone is equipped with a gas-liquid separation component, so that the cooled waste gas is input into the adsorption zone for adsorption treatment. The desorption zone is equipped with a microwave heating element, which is used for desorption after adsorption by the activated carbon plate (35). The exhaust gas condensation assembly includes a condensation chamber (15) located in the cooling zone. A liquid nitrogen input pipe (5) is installed on the outside of the condensation chamber (15), and a condensation pipe (16) is provided inside the condensation chamber (15). The output end of the condensation pipe (16) is connected to the gas-liquid separation assembly, and an exhaust gas input pipe (7) is installed at the input end of the condensation pipe (16). A hollow bushing (28) is installed in the middle of the outer shell (1). A vent hole (25) is provided on the upper outer side of the hollow bushing (28). The condensation chamber (15) is connected to the cooling zone, so that the liquid nitrogen vaporizes and moves upward along the axial direction of the outer shell (1) and enters the hollow bushing (28) through the vent hole (25).

2. The VOCs recovery and treatment device for a color-coated steel sheet production line according to claim 1, characterized in that: The outer shell (1) has a first arc plate (20) fixed inside the adsorption zone and a second arc plate (21) fixed inside the desorption zone. Both the first arc plate (20) and the second arc plate (21) have through slots (30) which are rotatably connected to the rotating frame (23).

3. A VOCs recovery and treatment device for a color-coated steel sheet production line according to any one of claims 1 or 2, characterized in that: The gas-liquid separation assembly includes a gas-liquid separation tube (19) fixed inside the outer shell (1). The lower end of the gas-liquid separation tube (19) is provided with a liquid accumulation chamber. The upper outer side of the gas-liquid separation tube (19) is fixed with a connecting pipe (39) communicating with the adsorption zone. A spiral plate (27) is fixed inside the gas-liquid separation tube (19). A gas-liquid input pipe (29) is installed at the output end of the condenser tube (16). The gas-liquid input pipe (29) inputs the waste gas tangentially into the gas-liquid separation tube (19) along the gas-liquid separation tube (19).

4. The VOCs recovery and treatment device for a color-coated steel sheet production line according to claim 3, characterized in that: The microwave heating element includes a microwave generator (22) fixed inside the outer shell (1). The microwave generator (22) is provided with a heating plate (31) for heating the activated carbon layer (35) so that the waste gas adsorbed on the activated carbon layer (35) is desorbed at high temperature. A vacuum pump (14) is fixed inside the bottom of the outer shell (1). The input end of the vacuum pump (14) is equipped with a manifold (26) that communicates with the desorption zone, and the output end of the vacuum pump (14) is equipped with a concentrated waste gas output pipe (6).

5. A VOCs recovery and treatment device for a color-coated steel sheet production line according to claim 4, characterized in that: The adsorption assembly further includes: The inner lining (36) is fixedly connected to one end of the partition plate (38); Bottom mesh plate (34) is fixed to the bottom of the inner lining (36); The top plate mesh (37) is installed between two adjacent isolation plates (38) and located at the top of the activated carbon layer plate (35).

6. The VOCs recovery and treatment device for a color-coated steel sheet production line according to claim 5, characterized in that: A driven shaft (12) is rotatably installed in the cooling zone. A small gear (13) is fixed on the outside of the driven shaft (12). A groove is provided in the middle of the outer side of the rotating frame (23). An external gear (24) that meshes with the small gear (13) is fixed in the groove.

7. A VOCs recovery and treatment device for a color-coated steel sheet production line according to claim 6, characterized in that: A motor (8) is fixed to the upper outer side of the outer shell (1). The output end of the motor (8) extends into the hollow bushing (28) and is equipped with an exhaust fan (32). The output end of the motor (8) is also fixed with a drive wheel (9). The upper end of the driven shaft (12) passes through the upper outer side of the outer shell (1) and is fixed with a driven wheel (11). A synchronous transmission belt (10) is provided between the driven wheel (11) and the drive wheel (9).

8. A method for VOCs recovery and treatment in a color-coated steel sheet production line, characterized in that: The VOCs recovery and treatment device for color-coated steel sheet production line according to any one of claims 1-7 specifically includes the following steps: S1. Collect and filter workshop exhaust gas; S2. The exhaust gas enters the exhaust gas condensation component through the exhaust gas inlet pipe (7) to cool and liquefy, forming a gas-liquid mixture; S3. The gas-liquid mixture is fed into the gas-liquid separation component for separation, the liquid phase is recovered, and the gas phase is fed into the adsorption zone for adsorption by the adsorption component. S4. The saturated adsorption component is transferred to the desorption zone, the microwave heating element heats the desorption, and the vacuum pump (14) draws the desorbed waste gas; S5. The exhaust fan (32) draws nitrogen into the hollow bushing (28), and the adsorption component in the cooling zone exchanges heat with nitrogen to achieve regeneration.

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