VOC recycling and discharging device and system

Abstract

Provided in the present invention are a VOC recycling and discharging device and system, which are applied to the technical field of recycling and discharging of harmful gas. In the VOC recycling and discharging device of the present invention, a first VOC condensation module and a VOC adsorption module recycles and treats VOC generated by an oven, and the first VOC condensation module is connected to the VOC adsorption module by means of a side flow pipeline; and the side flow pipeline is arranged in front of a first condensation assembly of the first VOC condensation module, and the VOC adsorption module is provided with a separate second condensation assembly. The effect of reducing the energy consumption of a heater in the oven is finally achieved by controlling the temperature of an outlet of the first condensation assembly, and the adsorption efficiency of the VOC adsorption module is improved by controlling the temperature of gas at an outlet of the second condensation assembly.

Description

A VOC recovery and emission device and system Technical Field

[0001] The present invention relates to the technical field of recovery and emission of harmful gases, and in particular to a VOC recovery and emission device and system. Background Art

[0002] VOCs refer to a class of volatile organic compounds that can be released from solid or liquid substances and enter the atmosphere; these compounds can come from various sources, such as battery manufacturing, automobile exhaust, industrial production, printing, painting, cleaning agents and some consumer products; they participate in photochemical reactions in the atmosphere and may have adverse effects on air quality and human health.

[0003] Exhaust emissions from lithium battery coating ovens have always been an important research direction for many manufacturing industries to solve air pollution problems. For example, the emission of NMP in the air of lithium battery cathode coating ovens. Excessive emission of NMP in the oven air can cause serious pollution, and the NMP in the air can be recovered and reused in the coating oven.

[0004] At present, in order to achieve the recovery and emission of VOCs, a treatment system with a first condensing component and a two-stage or multi-stage adsorption rotor is adopted. The VOCs in the gas at the oven outlet are condensed into liquid through the first condensing component, and a part of the gas is introduced into the rotor for adsorption and then discharged into the air. However, due to the large air volume at the oven outlet, most of the air enters the first condensing component and then flows back into the oven, and only a small part of the air enters the adsorption rotor. At the same time, due to the different temperature requirements of the adsorption rotor and the air flowing back into the oven, under this premise, how to use condensers with different cooling effects to provide air at different temperatures to reduce the energy consumption required by the condenser is an urgent technical issue in the industry.

[0005] Based on this, a VOC recovery and emission device and system is needed to provide different cooling effects through the side flow pipeline of the diversion port and multiple condensers to solve the above problems. Summary of the Invention

[0006] The present invention aims to provide a VOC recovery and emission device in a first aspect, comprising:

[0007] A first VOC condensation module, the first VOC condensation module includes a heat exchanger and a first condensation assembly, the first VOC condensation module is connected to a first VOC air outlet of the production equipment, the first VOC air outlet is connected to the hot end air inlet of the heat exchanger through a first working pipeline, the hot end air outlet of the heat exchanger is connected to the air inlet of the first condensation assembly, and the air outlet of the first condensation assembly is connected to the cold end air inlet of the heat exchanger through a first return pipeline, and the cold end air outlet of the heat exchanger is connected to the first VOC air outlet of the production equipment through a second return pipeline;

[0008] a VOC adsorption module, the VOC adsorption module being connected to the first VOC condensation module via a side flow pipeline, the side flow pipeline being connected between the air outlet of the hot end of the heat exchanger and the air inlet of the first condensation assembly, so as to separate the air from the air outlet of the hot end of the heat exchanger into a large airflow entering the first condensation assembly and a small airflow entering the VOC adsorption module via the side flow pipeline; the VOC adsorption module discharges the treated air through an exhaust pipeline;

[0009] The second VOC condensation module includes a second condensation component, which is located in the side flow pipeline upstream of the air inlet of the VOC adsorption module; the air temperature passing through the second condensation component is lower than the air temperature passing through the first condensation component.

[0010] Furthermore, the first condensing component includes a cooler and a first condenser. The cooling medium introduced into the cooler is cooling water, and the cooling medium introduced into the first condenser is chilled water. The temperature of the cooling water in the cooler is higher than the temperature of the chilled water in the first condenser.

[0011] Preferably, the VOC adsorption module includes at least one adsorption rotor; the adsorption rotor includes a regeneration zone, a cooling zone and at least one adsorption zone, and the air outlet of the second condensation component is connected to the adsorption zone and the cooling zone of the adsorption rotor; the cooling zone of the adsorption rotor is connected to the air inlet of the regeneration zone of the adsorption rotor through a third return line, and the air outlet of the regeneration zone of the adsorption rotor is connected to the side flow line through a fourth return line, and the connection position of the fourth return line and the side flow line is upstream of the air inlet of the second condensation component.

[0012] Furthermore, the adsorption wheel includes a first-stage wheel and a second-stage wheel; the first-stage wheel is connected in series with the second-stage wheel, the adsorption zone of the first-stage wheel is respectively connected to the adsorption zone and cooling zone of the second-stage wheel through series pipelines, and the regeneration zone air outlet of the second-stage wheel is connected to the third return line of the first-stage wheel through the fifth return line; the regeneration zone air outlet of the first-stage wheel is connected to the side flow line through the fourth return line.

[0013] Furthermore, at least one regeneration heater is provided on the third return line and / or the fifth return line.

[0014] Preferably, the first VOC condensation module is provided with a first fan, and the VOC adsorption module is provided with a second fan; a first air valve is provided on the side flow pipeline, and the first air valve controls a large air volume to enter the first condensation component and a small air volume to enter the VOC adsorption module; a second air valve is provided on the third return pipeline.

[0015] The static pressure of the gas at the inlet of the VOC adsorption module is controlled to be ≤1000Pa.

[0016] Furthermore, the VOC recovery and emission device is also connected to a second VOC air outlet, and the second VOC air outlet is connected to the side stream pipeline or the series pipeline through a second working pipeline.

[0017] In this solution, by connecting the second VOC air outlet to the fifth return line between the first-stage rotor and the second-stage rotor, the air processing volume of the first-stage rotor can be reduced, thereby reducing the diameter of the first-stage rotor and reducing equipment investment.

[0018] Preferably, the first VOC air outlet is the return air outlet and the exhaust air outlet of the coating machine oven, and the second VOC air outlet is the head and tail exhaust ducts of the coating machine oven.

[0019] In a second aspect, the present invention provides a VOC recovery and emission system, comprising production equipment and the above-mentioned VOC recovery and emission device.

[0020] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0021] First, the present invention sets the connection position between the side stream pipeline and the first VOC condensation module before the first condensation component, and sets a separate condenser after the side stream pipeline; since the VOC adsorption modules have certain requirements for the reflux gas temperature, the side stream pipeline is usually set after the first condensation component; and the heat exchanger does not need to control the outlet temperature of the first condensation component too low, and the VOC adsorption module has a low requirement for the condenser outlet temperature. The existing technology generally controls the outlet temperature of the first condensation component below 20°C, and the present invention only needs to control it at 25°C; and since the gas refluxes into the oven is the majority, the present invention can achieve substantial energy saving, and achieve the dual effects of reducing the amount of chilled water required for the condenser itself and reducing the amount of heating by the heater in the oven.

[0022] Second, the outlet gas temperature of the second condensation component of the present invention is controlled below 20°C, with the optimal value being 10~15°C, which can greatly reduce the NMP content in the exhaust gas; usually, in order to save energy, the gas drawn out from the first condensation component is often only controlled below 20°C, and the present invention can further reduce the drawn-out gas temperature through a separately set second condensation component, thereby improving the efficiency of the adsorption wheel and reducing the NMP content in the exhaust gas.

[0023] Third, the VOC adsorption module of the present invention includes two adsorption rotors. Since the NMP concentration in the regeneration outlet gas of the secondary rotor (one example: 65.2 ppm) is lower than the NMP concentration in the outlet gas of the cooling zone of the primary rotor (one example: 169 ppm), the purification efficiency of the exhaust gas purification equipment can be improved, and the NMP content in the exhaust gas can be reduced to near zero emissions.

[0024] Fourth, the effective area ratio of the cooling zone, regeneration zone and adsorption zone of the first-stage rotor of the present invention is designed to be 1:2:12, and the effective area ratio of the cooling zone, regeneration zone and adsorption zone of the second-stage rotor is designed to be 1:1:10. This ratio can achieve the best adsorption efficiency.

[0025] Fifth, a fan is installed in the first return line to overcome air resistance and deliver air faster in the flow path; a filter is installed in the second return line to further remove impurities in the gas flow path, such as dust and harmful substances; an air valve is installed in the side flow line to control the air volume ratio entering the VOC adsorption module, thereby achieving the best adsorption effect.

[0026] Sixth, when the NMP concentration in the exhaust air at the head and tail of the coating machine oven is lower than a certain value, the present invention can also directly introduce the exhaust air at the head and tail of the coating machine oven into the space between the first-stage rotor and the second-stage rotor, and mix it with the air at the outlet of the first-stage rotor before entering the second-stage rotor; this can reduce the amount of air processed by the first-stage rotor, thereby reducing the diameter of the first-stage rotor and reducing equipment investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] FIG1 is a schematic structural diagram of a first embodiment of a VOC recovery and emission device according to the present invention;

[0029] FIG2 is a schematic structural diagram of a first condensing assembly according to a first embodiment of the present invention;

[0030] FIG3 a is a schematic structural diagram of a second embodiment of a VOC recovery and emission device according to the present invention;

[0031] FIG3 b is a schematic structural diagram of another implementation of the second embodiment of the VOC recovery and emission device of the present invention;

[0032] FIG4 is a schematic structural diagram of a third embodiment of a VOC recovery and emission device according to the present invention;

[0033] FIG5 a is a schematic structural diagram of a third embodiment of a VOC recovery and emission device according to the present invention;

[0034] FIG5 b is a schematic structural diagram of another implementation of the third embodiment of the VOC recovery and emission device of the present invention. Description of Reference Numerals

[0035] 1. First VOC condensation module; 11. Heat exchanger; 12. Filter; 13. First condensation component; 131. Cooler; 132. First condenser; 14. First air valve; 15. Recovery tank; 16. Diversion port; 2. VOC adsorption module; 21. Second condensation component; 22. Adsorption rotor; 221. Primary rotor; 222. Secondary rotor; 2201. Adsorption zone; 2202. Cooling zone; 2203. Regeneration zone; 23. Regeneration heater; 24. Regeneration fan; 25. External exhaust fan; 26. Second air valve; 31. First VOC air outlet; 32. Second VOC air outlet. DETAILED DESCRIPTION

[0036] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present invention, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement the device and / or practice the method.

[0039] It should also be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0040] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples, however, one skilled in the art will appreciate that the examples can be practiced without these specific details.

[0041] At the same time, in this specification, descriptions involving orientations, such as up, down, left, right, front, back, inside, outside, longitudinal, lateral, vertical, horizontal, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0042] Furthermore, in the description of this specification, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. The components mentioned in the present invention are connected in sequence, which only represents the relative position relationship between the components and the circulation direction of the corresponding working fluid and gas. Without destroying the relative position and connection sequence of the components, those skilled in the art can set other different intermediate components between the components connected in sequence according to actual needs, such as fans, etc. "Connected in sequence" should not be understood only as the components must be directly connected in sequence.

[0043] To maintain the maximum NMP concentration in the oven air of a lithium battery cathode coating machine within a safe range, conventional technology uses a circulating fan to transport the high-temperature, high-concentration NMP gas from the oven to a heat exchanger 11, cooling coil, and condensing coil. This process recovers heat energy while simultaneously cooling the gas and condensing the NMP vapor contained in the gas into a liquid for recovery. Design calculations show that as long as the amount of NMP condensed in the heat exchanger 11 and cooling and condensing coils is no less than the amount of NMP emitted from the cathode electrode in the coating machine oven, the NMP concentration in the oven air can be maintained within the required safe range.

[0044] The production equipment in the present application includes but is not limited to a coating machine oven, and the waste gas to be recycled and treated includes but is not limited to organic gases such as NMP; for ease of description, the production equipment in the following preferred embodiments is taken as an example of a coating machine oven, and the waste gas is described as an example of NMP, but it should be understood that the production equipment described in the present application should not be limited to the coating machine oven. Any production device that generates organic gases and other waste gases during production and requires air supply and exhaust, such as lithium battery coating ovens, printing, semiconductors, adhesive tape manufacturing, etc., can use the solution of the present application. The coating machine oven should not be understood as a limitation on the production equipment in the present application, and NMP should not be understood as a limitation on the waste gas in the present application. Other coating-related organic gases, such as toluene, N,N-dimethylacetamide (DMAC), and N,N-dimethylformamide (DMF) can also be recovered and discharged using the VOC recovery and emission device of the present invention.

[0045] The production equipment in this application is maintained in a slightly negative pressure state in order to prevent the high-temperature and high-concentration NMP gas in the production equipment from leaking into the surrounding environment; however, it should be understood that the production equipment described in this application may also be in a positive pressure state, and maintaining the production equipment in a negative pressure state cannot be understood as limiting the scope of the claims of the present invention; preferably, the static pressure of the inlet gas of the VOC adsorption module of this application should be controlled at ≤1000Pa. Example 1:

[0046] Figure 1 shows a schematic structural diagram of a VOC recovery and emission device according to a first embodiment of the present invention, which includes a first VOC air outlet 31, a heat exchanger 11, a first condensation assembly 13, and a VOC adsorption module 2. Accordingly, the hot-end air inlet of the heat exchanger 11 and the air outlet 31 of the first VOC air outlet of the production equipment are gas-connected in sequence to form a first working pipeline. The air inlet of the first condensation assembly 13 and the hot-end air outlet of the heat exchanger 11 are gas-connected in sequence. A diversion port 16 is provided between the air outlet of the heat exchanger and the air inlet of the first condensation assembly so that part of the air drawn out from the air outlet of the heat exchanger is diverted and enters the VOC adsorption module 2 through a side stream pipeline. In one embodiment, the side stream management is provided with at least one second condensation assembly 21. The first condensation assembly 13 is also connected to the cold-end air inlet of the heat exchanger 11 through a first return pipeline, and is in communication with a second return pipeline of the hot-end air outlet of the heat exchanger 11. The second return pipeline is connected to the return air outlet of the first VOC air outlet 31 of the production equipment.

[0047] The gas flow path also includes a power mechanism such as a fan, which is used to increase the gas pressure and discharge the gas, thereby playing the role of supplying air in the gas flow path; accordingly, the VOC adsorption module 2 in this embodiment can be a device based on a rotor structure or any other device that can achieve NMP adsorption.

[0048] In this embodiment, the air containing NMP generated at the outlet of the first VOC air outlet 31 is first cooled by the heat exchanger 11. A portion of the air is separated from the NMP in the air by the action of the first condensing component 13 and then circulated into the heat exchanger 11 again, and finally flows back to the return air outlet of the first VOC air outlet 31; the other portion is purified by the VOC adsorption module 2 to reduce the NMP concentration to the emission standard before being discharged.

[0049] Figure 2 is a schematic structural diagram of the first condensing component of the first embodiment of the present invention. In this embodiment, the above-mentioned first condensing component 13 includes: a cooler 131 and a first condenser 132, and the first condenser 132 is also provided with a water baffle; and the heat exchanger 11, the cooler 131 and the first condenser 132 are connected to a recovery pipeline to accumulate excess NMP in a recovery tank 15; an air filter 12 is provided on the second return pipeline; the air filter 12 can first absorb impurities in the air to prevent them from entering the core components and forming difficult-to-clean dirt and affecting the efficacy.

[0050] Among them, the cooler 131 is connected to the air outlet of the heat exchanger 11; the first condensation component 13 includes at least the cooler 131 and the first condenser 132. It should be understood that the above "include" means that there must be at least a cooler 131 and a first condenser 132 on the fresh air path, and it has nothing to do with the relative position between the two. The relative position between the cooler 131 and the first condenser 132 can be interchanged according to actual conditions, and their relative position should not be understood as a limitation on the scope of protection of the independent claim. After the heat exchanger 11 is connected to the first return line, it is connected at least through the cooler 131 and the first condenser 132. Here, "at least" means that after the heat exchanger 11 is connected to the first return line, the mixed gas must at least pass through the cooler 131 and the first condenser 132. As for whether it passes through other components, such as: a fan or other possibly arranged components, and the arrangement order between various components, there is no limitation, nor can it be understood as a limitation on the scope of protection of the claims; in this embodiment, the connection position of the side flow line and the first VOC condensation module is set before the first condensation component 13, and a separate second condensation component 21 is set after the side flow line to further reduce the concentration of NMP in the air diverted to the VOC adsorption module 2 through condensation; generally, since the VOC adsorption module 2 has certain requirements on the temperature of the return gas, the side flow line is usually set after the first condensation component 13. In this embodiment, the heat exchanger 11 does not have a requirement for the outlet temperature of the first condensing component 13 to be too low, and the VOC adsorption module 2 has a relatively low requirement for the outlet temperature of the first condenser 132; in the prior art, the outlet temperature of the first condensing component 13 is generally controlled below 20°C, while this embodiment only needs to control the temperature at 25°C to meet the requirement; since the gas flowing back into the oven accounts for the majority, this embodiment achieves a significant energy-saving effect, which not only reduces the amount of chilled water required for the first condenser 132 itself, but also reduces the heating demand of the heater in the oven, achieving a double energy-saving effect. Example 2:

[0051] Referring to Figure 3a, compared with the above embodiment, in order to further improve the NMP adsorption effect and reduce the NMP emission concentration, the VOC adsorption module 2 of this embodiment includes an adsorption rotor 22, and a second condensation component 21 is arranged before the adsorption rotor 22. The outlet gas temperature of the second condensation component 21 of this embodiment is strictly controlled below 20°C, and the optimal value is usually set between 10 and 15°C, which greatly reduces the NMP content in the exhaust gas; generally, for energy saving considerations, the gas drawn out from the first condensation component 13 is often controlled only below 20°C; however, this embodiment further reduces the temperature of the drawn-out gas by separately setting the second condensation component 21, which not only improves the working efficiency of the adsorption rotor 22, but also effectively reduces the NMP content in the exhaust gas, so that the environmental protection index of the exhaust gas reaches a higher level.

[0052] Referring to FIG3b, in this embodiment, the adsorption rotor 22 may further include a primary rotor 221 and a secondary rotor 222, wherein the primary rotor 221 and the secondary rotor 222 include at least one adsorption zone 2201, a cooling zone 2202 and a regeneration zone 2203, and an external exhaust fan 25 is provided behind the adsorption zone 2201 of the secondary rotor 222; the first VOC condensation module 1 is connected to the adsorption zone 2201 and the cooling zone 2203 of the primary rotor 221 after being diverted by a side flow pipeline. 2; accordingly, the air outlets of the cooling zones 2202 of the primary rotor 221 and the secondary rotor 222 are connected to their respective regeneration zones 2203 via a third return line. The primary rotor 221 and the secondary rotor 222 are connected in series. Specifically, the air outlet of the adsorption zone 2201 of the primary rotor 221 is split and connected to the air inlet of the adsorption zone 2201 of the secondary rotor 222, while the air outlet of the regeneration zone 2203 of the secondary rotor 222 is connected to the third return line in the primary rotor 221. The VOC adsorption module 2 of this embodiment employs two adsorption rotors 22, which are capable of efficiently adsorbing and treating NMP in exhaust gas. By maintaining the NMP concentration in the regeneration outlet gas of the secondary rotor 222 at a low level (e.g., approximately 65.2 ppm), the NMP concentration in the outlet gas of the cooling zone 2202 of the primary rotor 221 is reduced (e.g., enabling the exhaust gas purification equipment to more effectively remove NMP, thereby significantly reducing the NMP content in the exhaust gas to near-zero emission levels).

[0053] Preferably, the external exhaust fan 25 is arranged on the outlet side of the adsorption zone 2201 of the secondary wheel 222, or on the inlet side of the adsorption zone 2201 of the secondary wheel 222, and the regeneration fan 24 is arranged on the outlet side of the regeneration zone 2203 of the primary wheel 221, so as to ensure that the air inside the VOC adsorption module 2 is at a positive pressure or even a negative pressure state of not more than 650Pa, thereby ensuring that the external exhaust gas purification equipment can achieve high-efficiency treatment of the external exhaust gas.

[0054] In this embodiment, a regeneration heater 23 is provided on the third return line; the air with a low NMP concentration drawn from the air outlet of the cooling zone 2202 is heated by the regeneration heater 23 before entering the regeneration zone 2203. The regenerated and heated regeneration air then passes through the regeneration zone 2203 of the adsorption wheel 22 to adsorb NMP in the air.

[0055] The first-stage rotor 221 is connected to the side flow pipeline through the fourth return pipeline, and a regeneration fan 24 is provided on the fourth return pipeline; a part of the air at the inlet of the adsorption zone 2201 of the first-stage rotor 221 is introduced into the cooling zone 2202 of the first-stage rotor 221 → the outlet gas of the cooling zone 2202 of the first-stage rotor 221 is combined with the outlet gas of the regeneration zone 2203 of the aforementioned second-stage rotor 222 and then introduced into the regeneration heater 23 of the first-stage rotor 221 → the regeneration zone 2203 of the first-stage rotor 221 → the regeneration zone 2203 of the first-stage rotor 221 → the regeneration fan 24, and the gas at the outlet of the regeneration fan 24 is mixed with the gas at the outlet of the first VOC condensation module 1 and is again introduced into the second condensation component 21. Example 3:

[0056] Referring to FIG. 4 , in this embodiment, compared to the second embodiment, the side stream pipeline is further fed by the second VOC air outlet 32 ​​. To prevent high-temperature, high-concentration NMP gas in the production equipment from leaking into the surrounding environment, the production equipment needs to be maintained at a slightly negative pressure. Therefore, the air volume returning to the return air outlet of the first VOC air outlet 31 is generally only about 94% of the air volume at the outlet of the first VOC air outlet 31 . Approximately 6% of the gas discharged from the outlet of the first VOC air outlet 31 needs to be purified to meet environmental exhaust standards before being discharged into the atmosphere. Since the NMP concentration in the return air outlet returning to the first VOC air outlet 31 generally only needs to be ≤400ppm to meet the safety requirements of the production equipment, and from the perspective of saving energy consumption of the heater (not shown in the figure) in the production equipment, the higher the temperature of the air at the outlet of the first condenser 132, the better. Based on the two points of return air temperature and NMP concentration, setting the outlet temperature of the first condenser 132 to below 26°C is an optimal design value; and the outlet gas temperature of the second condensation component 21 is controlled below 20°C, and the optimal value is 10~15°C.

[0057] Referring to Figure 5a, in one possible implementation scenario, an oven is used in the coating and drying process for battery cathode materials. The production equipment is a coater oven. First VOC vent 31 serves as the coater oven's air outlet, while second VOC vent 32 serves as the oven's head and tail exhaust vents. A first air valve 14 is installed on the sidestream duct, and a second air valve 26 is installed at the outlet of the cooling zone 2202 of the first-stage rotor 221. The oven exhaust rate is 100,000 Nm³ / h, the temperature is 150°C, the exhaust NMP concentration is 3250 ppm (<25% LEL), and the emission requirement is NMPs ≤ 8 mg / Nm³. Specifically, environmental data can be obtained from key nodes of the VOC recovery and emission device (see Figure 4), yielding the following NMP concentration status table:

[0058]

[0059] From the table, it can be seen that at point C after passing through the first condensing component 13, the gas temperature in this embodiment is controlled to be 26°C, and the NMP concentration is 395.5ppm, which is lower than the safety standard of 400ppm; at the same time, the NMP concentration in the discharged gas is only 0.45ppm; it can be seen that since the return air to the oven accounts for as high as 94%, its temperature is controlled at 26°C, which is higher than the normal 20°C; since the cooling medium introduced by the cooler 131 is chilled water from the cooling tower, and the cooling medium introduced by the first condenser 132 is chilled water from the refrigerator, the consumption of cooling water and chilled water are reduced, achieving the effect of energy saving and emission reduction; and the air volume diverted to the VOC adsorption module 2 is only 6%. Although the second condensing component 21 reduces its temperature to 15°C, due to the small air volume, the impact on the consumption of cooling water is small; specifically, in one embodiment, the cooling water consumption of the cooler 131 is 44055.1 kg / h, and the chilled water consumption of the first condenser 132 is 59964.9 kg / h, while the freezer consumption of the second condensing component 21 is only 23155 kg / h; it should be understood that the use of chilled water and cooling water in this embodiment is only preferred, and any device that can achieve air condensation can be used as the first condenser 132 and the cooler 131. The use of cooling water and chilled water to condense the air should not be understood as a limitation of the claims of the present invention.

[0060] It should be pointed out that the cooling water used in this embodiment comes from the cooling tower, and the chilled water used from the refrigerator is only preferred. In other embodiments, cooling water and chilled water from different sources can be used to achieve the technical effect of saving cooling water and chilled water, thereby realizing energy conservation and emission reduction.

[0061] In one example, as shown in FIG5b , the second VOC air outlet 32 ​​is directly connected between the primary rotor 221 and the secondary rotor 222, and the specific connection position is between the air outlet of the adsorption zone 2201 of the primary rotor 221 and the air inlet of the adsorption zone 2201 of the secondary rotor 222; by mixing the air from the second VOC air outlet with the air from the air outlet of the adsorption zone 2201 of the primary rotor 221, the amount of air processed by the primary rotor is reduced, thereby reducing the diameter of the primary rotor and reducing equipment investment; more preferably, when the NMP concentration in the exhaust gas at the head and tail of the coating machine oven is lower than 25 ppm, the air is directly introduced between the primary rotor and the secondary rotor.

[0062] The working principle of this embodiment is as follows: the low dew point dry air introduced from the outside is heated after the operation of the oven, and is introduced into the heat exchanger 11 from the oven to be cooled. Then, it is diverted at the diversion port 16, and part of the gas flows through the first condensation component 13 for NMP condensation and recovery. Since the oven maintains a negative pressure state, the air passing through the first condensation component 13 enters the heat exchanger 11 again and returns to the oven; the other part of the gas enters the VOC adsorption module 2 through the side flow pipeline.

[0063] In the VOC adsorption module 2, exhaust air from the coating machine oven head and tail is introduced and merged with the gas diverted in the side flow pipeline to form mixed NMP air. After the mixed NMP air is further condensed by the second condensation component 21, it passes through the adsorption zone 2201 and the cooling zone 2202 of the adsorption rotor 22 and then flows back to the regeneration zone 2203 of the adsorption rotor 22 to desorb NMP in the mixed NMP air. In one possible embodiment, the ratio of the adsorption air volume flowing through the adsorption zone 2201 of the adsorption rotor 22, the cooling air volume flowing through the cooling zone 2202 of the adsorption rotor 22, and the regeneration air volume flowing through the dehumidification rotor regeneration zone 2203 is 13.2:2.2:1; in one embodiment, the ratio of the adsorption air volume flowing through the adsorption zone 2201 of the adsorption rotor 22, the cooling air volume flowing through the cooling zone 2202 of the adsorption rotor 22, and the regeneration air volume flowing through the dehumidification rotor regeneration zone 2203 is 13.2:2.2:1. In a possible embodiment, the ratio of the adsorption air volume flowing through the adsorption zone 2201 of the adsorption wheel 22, the cooling air volume flowing through the cooling zone 2202 of the adsorption wheel 22, and the regeneration air volume flowing through the dehumidification wheel regeneration zone 2203 is 10:1:1; when the number of adsorption wheels 22 is 2, the air volume ratio of the first-stage wheel 221 and the second-stage wheel 222 is preferably the above-mentioned ratio, and more preferably the ratio of the adsorption zone 2201: cooling zone 2202: regeneration zone 2203 of the first-stage wheel 221 is 13.2:2.2:1, and the ratio of the second-stage wheel 222 is 10:1:1; it should be understood that the above-mentioned air volume ratio is only preferred and should not be understood as limiting the scope of protection of the independent claims of the present invention.

[0064] In addition, the gas at the outlet of the regeneration zone 2203 of the adsorption rotor 22 flows back to the side stream pipeline and merges with the NMP air at the diversion port 16 to achieve cyclic adsorption of NMP in the air, and is finally discharged through the external exhaust fan 25. According to the NMP emission requirements, different specifications and quantities of adsorption rotors 22 can be selected as needed. Preferably, in this embodiment, the number of adsorption rotors 22 selected is 2, the specifications of the first-stage rotor 221 are: φ1740×400, and the rotation speed is preferably: n=4 rph; the specifications of the second-stage rotor 222 are: φ1740×400, and the rotation speed is preferably: n=3 rph.

[0065] Therefore, in general, the present invention sets the diversion point before the first condensation component 13 and separately sets the second condensation component 21 before the adsorption wheel 22. This not only reduces the energy consumption of the heater in the oven through a higher reflux gas temperature, but also reduces the diversion gas to a lower temperature through the second condensation component 21, thereby improving the efficiency of the adsorption wheel 22 and achieving a higher NMP removal effect.

[0066] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A VOC recovery and emission device, characterized in that: include: a first VOC condensation module, the first VOC condensation module comprising a heat exchanger and a first condensation assembly, the first VOC condensation module being connected to a first VOC air outlet of the production equipment, the first VOC air outlet being connected to an air inlet of a hot end of the heat exchanger via a first working pipeline, an air outlet of the hot end of the heat exchanger being connected to an air inlet of the first condensation assembly, and an air outlet of the first condensation assembly being connected to an air inlet of a cold end of the heat exchanger via a first return pipeline, and an air outlet of the cold end of the heat exchanger being connected to the first VOC air outlet of the production equipment via a second return pipeline; a VOC adsorption module, the VOC adsorption module being connected to the first VOC condensation module via a side flow pipeline, the side flow pipeline being connected between the air outlet of the hot end of the heat exchanger and the air inlet of the first condensation assembly, so as to separate the air from the air outlet of the hot end of the heat exchanger into a large airflow entering the first condensation assembly and a small airflow entering the VOC adsorption module via the side flow pipeline; the VOC adsorption module discharges the treated air through an exhaust pipeline; The second VOC condensation module includes a second condensation component, which is located in the side flow pipeline upstream of the air inlet of the VOC adsorption module; the temperature of the air passing through the second condensation component is lower than the temperature of the air passing through the first condensation component.

2. The VOC recovery and emission device according to claim 1, characterized in that: The first condensing component includes a cooler and a first condenser. The cooling medium introduced into the cooler is cooling water, and the cooling medium introduced into the first condenser is chilled water. The temperature of the cooling water in the cooler is higher than the temperature of the chilled water in the first condenser.

3. The VOC recovery and emission device according to claim 1, characterized in that: The VOC adsorption module includes at least one adsorption rotor; the adsorption rotor includes a regeneration zone, a cooling zone and at least one adsorption zone, and the air outlet of the second condensation component is connected to the adsorption zone and the cooling zone of the adsorption rotor; the cooling zone of the adsorption rotor is connected to its own regeneration zone air inlet through a third return pipe, and the regeneration zone air outlet of the adsorption rotor is connected to the side flow pipe through a fourth return pipe, and the connection position of the fourth return pipe and the side flow pipe is upstream of the air inlet of the second condensation component.

4. The VOC recovery and emission device according to claim 3, characterized in that: The adsorption wheel includes a first-stage wheel and a second-stage wheel; the first-stage wheel and the second-stage wheel are connected in series, the adsorption zone of the first-stage wheel is respectively connected to the adsorption zone and the cooling zone of the second-stage wheel through series pipelines, the regeneration zone air outlet of the second-stage wheel is connected to the third return line of the first-stage wheel through the fifth return line; the regeneration zone air outlet of the first-stage wheel is connected to the side flow line through the fourth return line.

5. The VOC recovery and emission device according to claim 4, characterized in that: At least one regeneration heater is provided on the third return line and / or the fifth return line.

6. The VOC recovery and emission device according to claim 5, characterized in that: The first VOC condensation module is provided with a first fan, and the VOC adsorption module is provided with a second fan; a first air valve is provided on the side flow pipeline, and the first air valve controls a large air volume to enter the first condensation component and a small air volume to enter the VOC adsorption module; a second air valve is provided on the third return pipeline.

7. The VOC recovery and emission device according to any one of claims 1 to 6, characterized in that: The static pressure of the gas at the inlet of the VOC adsorption module is controlled to be ≤1000Pa.

8. The VOC recovery and emission device according to claim 4, characterized in that: The VOC recovery and emission device is further connected to a second VOC air outlet, and the second VOC air outlet is connected to the series pipeline or the side stream pipeline through a second working pipeline.

9. The VOC recovery and emission device according to claim 8, characterized in that: The first VOC air outlet is the return air outlet and the exhaust air outlet of the coating machine oven, and the second VOC air outlet is the head and tail exhaust ducts of the coating machine oven.

10. A VOC recovery and emission system, comprising production equipment and the VOC recovery and emission device according to any one of claims 1 to 9.

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