Dual-mode organic gas recovery and purification device, recovery system and mode control method

Abstract

The invention provides a dual-mode organic gas recovery and purification device, an organic solvent recovery system and a mode control method, and is applied to the technical field of organic waste gas recovery. The recovery and purification device comprises a main heat exchange module, a cold air supply module, a condensation recovery module and an adsorption rotating wheel; an air inlet of the condensation recovery module is communicated with a hot air outlet of the main heat exchange module, the adsorption rotating wheel at least comprises an adsorption area and a regeneration area and further comprises a first pipeline and a second pipeline, air inlets of the first pipeline and the second pipeline are both communicated with an air outlet of the condensation recovery module, and an air outlet of the first pipeline is communicated with an inlet of the adsorption area; according to the organic waste gas recycling device and system, the recycling treatment mode can be flexibly adjusted according to the boiling point characteristic of organic waste gas to be recycled, and therefore the comprehensive recycling efficiency of the organic waste gas recycling device and system on the organic gas is improved.

Description

Technical Field

[0001] The present application relates to the technical field of organic gas recovery and purification, and in particular to a dual-mode organic gas recovery and purification device, a recovery system, and a mode control method. Background Art

[0002] It is known that for high-boiling-point organic waste gas with large air volume and low concentration, since the saturated vapor pressure of the volatile organic compounds (VOCs) contained therein is low, it is easier to achieve the operating conditions of condensation recovery at the same temperature, so the recovery efficiency of the condensation recovery method is higher and the energy consumption is relatively low. However, for low-boiling-point organic waste gas with large air volume and low concentration, since the saturated vapor pressure of the organic compounds contained therein is high, the energy consumption of the condensation equipment will be greatly increased if the organic compounds are to be recovered and purified only by the condensation recovery method. In order to reduce energy consumption, the prior art usually recycles and purifies the above-mentioned organic waste gas by combining adsorption concentration by an adsorption wheel and condensation treatment by a condensation device. Since the adsorption wheel has a high concentration multiple, it can condense the waste gas with large air volume and low concentration into a regenerated gas with small air volume and high concentration, so that the refrigeration load of the subsequent condensation treatment equipment can be greatly reduced, and the energy consumption is greatly reduced.

[0003] Existing VOCs gas recovery and treatment equipment generally includes a heat exchanger assembly, a condensation recovery assembly and an adsorption concentration device, wherein the adsorption concentration device includes an adsorption wheel and a regeneration heater, the adsorption wheel includes an adsorption zone, a cooling zone and a desorption zone, the heat exchanger assembly performs heat exchange between the organic waste gas discharged from the production device and the low-temperature tail gas returned to the production device to recover the organic solvent, the condensation recovery module is used to condense the gas from the heat exchanger assembly and the regenerated gas after desorption and concentration in the desorption zone of the adsorption wheel and recover the organic solvent, the adsorption wheel is used to perform adsorption recovery and concentrated regeneration on the remaining tail gas discharged from the outlet of the condensation recovery module, and part of the remaining low-temperature tail gas after adsorption in the adsorption zone is discharged, and part is returned to the production device after heat exchange by the heat exchange assembly.

[0004] The equipment has at least the following defects during the use stage, such as the equipment is only suitable for treating low-boiling point organic waste gas. If it is used to treat high-boiling point organic waste gas, it will not only increase the regeneration energy consumption of the adsorption wheel, but also reduce the comprehensive recovery efficiency of the organic waste gas. Specifically, for the existing VOCs gas recovery and treatment equipment, whether it is for low-boiling point organic waste gas or high-boiling point organic waste gas, the organic compounds in the gas are recovered and purified by adsorption concentration of the adsorption wheel plus condensation treatment of the condensation equipment. However, high-boiling point organic waste gas is often difficult to desorb after adsorption by the adsorption wheel, which will cause polymerization blockage and greatly weaken the adsorption efficiency of the adsorption wheel. If the adsorption consumables in the wheel are not updated in time, it will affect the subsequent recovery and treatment of low-boiling point organic waste gas. Furthermore, high-boiling point organic waste gas is more suitable for recovery by condensation recovery, that is, compared with the method of first adsorbing and concentrating the organic waste gas by the adsorption wheel and then introducing it into the condensation recovery module under the same temperature conditions for condensation recovery, the improvement of the organic waste gas recovery efficiency by directly operating the temperature conditions of the condensation recovery module is more obvious, and the operating cost and energy use cost of the overall equipment are lower.

[0005] In summary, there is an urgent need for a recovery and purification device that can flexibly adjust the recovery and treatment mode according to the boiling point characteristics of the organic waste gas to be recovered to improve the comprehensive recovery efficiency. Summary of the invention

[0006] In view of this, the embodiments of the present specification provide a dual-mode organic gas recovery and purification device, a recovery system and a mode control method. The recovery and purification device and the recovery system have the advantage of being able to flexibly adjust the recovery and treatment mode according to the boiling point characteristics of the organic waste gas to be recovered. The mode control method has the advantage of being able to greatly improve the adaptability and flexibility of the recovery and purification device and the recovery system.

[0007] The embodiments of this specification provide the following technical solutions: A dual-mode organic gas recovery and purification device is configured to switch between a high-boiling point treatment mode and a low-boiling point treatment mode, comprising: an input port, an output port and a return air port; a main heat exchange module, whose hot air inlet is connected to the input port, and whose cold air outlet is connected to the return air port; a cold air supply module, whose air outlet is connected to the cold air inlet of the main heat exchange module; a condensation recovery module, whose air inlet is connected to the hot air outlet of the main heat exchange module; an adsorption wheel, which at least includes an adsorption zone and a regeneration zone, the outlet of the adsorption zone is connected to the output port, and the outlet of the regeneration zone is connected to the air inlet of the condensation recovery module; and a first pipeline and a second pipeline, both of which have air inlets connected to the air outlet of the condensation recovery module, and the air outlet of the first pipeline is connected to the inlet of the adsorption zone, and the second pipeline bypasses the adsorption wheel in the air flow direction and the pipeline air outlet is connected to the device output port; the first pipeline and the second pipeline are both controlled to be turned on or off and have mutually exclusive on-off states to facilitate the realization of different treatment modes.

[0008] In order to optimize the above scheme, the following measures are also taken: As a preferred embodiment, the cold air supply module includes: a third pipeline, whose air inlet is for fresh air to enter, and whose air outlet is connected to the cold air inlet of the main heat exchange module.

[0009] As a preferred embodiment, the cold air supply module includes: a fourth pipeline and a fifth pipeline, the air outlets of both pipelines are connected to the cold air inlet of the main heat exchange module, the air inlet of the fourth pipeline is connected to the air outlet of the condensation recovery module, and the air inlet of the fifth pipeline is connected to the outlet of the adsorption zone of the adsorption wheel; the fourth pipeline and the fifth pipeline are both controlled to be turned on or off and have mutually exclusive on-off states.

[0010] As a preferred embodiment, the cold air supply module includes: a third pipeline, a fourth pipeline and a fifth pipeline, the air outlets of the three pipelines are all connected to the cold air inlet of the main heat exchange module, the air inlet of the third pipeline is used for fresh air, the air inlet of the fourth pipeline is connected to the air outlet of the condensation recovery module, and the air inlet of the fifth pipeline is connected to the outlet of the adsorption zone; the third pipeline, the fourth pipeline and the fifth pipeline are all controlled to be turned on or off and when one of the pipelines is turned on, the other two pipelines are disconnected.

[0011] As a preferred embodiment, it also includes an auxiliary heat exchange module, the hot gas inlet of the auxiliary heat exchange module is connected to the outlet of the regeneration zone, and the hot gas outlet of the auxiliary heat exchange module is connected to the air inlet of the condensation recovery module.

[0012] As a preferred embodiment, the cold air inlet of the auxiliary heat exchange module is communicated with the outlet of the adsorption zone, and the cold air outlet of the auxiliary heat exchange module is communicated with the device output port.

[0013] As a preferred embodiment, the adsorption wheel also includes a cooling zone and a regeneration heater, the air inlet of the cooling zone is connected to the external air source and / or the air outlet of the first pipeline, the air inlet of the regeneration heater is connected to the air outlet of the cooling zone, and the air outlet of the regeneration heater is connected to the inlet of the regeneration zone.

[0014] The embodiments of this specification also provide an organic solvent recovery system for recovering organic solvents from high-temperature exhaust gas containing organic solvents discharged from production equipment, characterized in that the recovery system includes the aforementioned dual-mode organic gas recovery and purification device, wherein the input port of the recovery and purification device is connected to the exhaust port of the production equipment, and the return air port of the recovery and purification device is connected to the air inlet of the production equipment.

[0015] The presently described embodiment also provides a mode control method for the above-mentioned dual-mode organic gas recovery and purification device, which method includes the following steps: S1, comparing the boiling point temperature of the current organic gas to be treated with the set temperature reference value, if it is lower than the temperature reference value, executing S2-1, if it is higher than the temperature reference value, executing S2-2; S2-1, operating the device and executing the low boiling point treatment mode, specifically, connecting the first pipeline and disconnecting the second pipeline at the same time, thereby allowing the organic gas discharged through the condensation recovery module to enter the adsorption zone and cooling zone of the adsorption wheel from the first pipeline, while preventing the exhaust gas discharged through the condensation recovery module from entering the output port of the device from the second pipeline; S2-2, operating the device and executing the high boiling point treatment mode, specifically, connecting the second pipeline and disconnecting the first pipeline, thereby allowing the organic gas discharged through the condensation recovery module to enter the output port of the device from the second pipeline, while preventing the exhaust gas discharged through the condensation recovery module from entering the adsorption zone and cooling zone of the adsorption wheel from the first pipeline.

[0016] As a preferred embodiment, in S2-1, while operating the device, it is determined whether the current operating conditions allow the execution of the first return air mode. If so, the first return air mode is executed, that is, the third pipeline is connected and the fourth pipeline and the fifth pipeline are disconnected, so that the third pipeline becomes the only cold air supply pipeline and allows fresh air to enter the main heat exchange module and be discharged from the return air port of the device; if not, it is determined whether the current operating conditions allow the execution of the second return air mode. If so, the second return air mode is executed, that is, the fourth pipeline is connected and the third pipeline and the fifth pipeline are disconnected, so that the fourth pipeline becomes the only cold air supply pipeline and allows the exhaust gas discharged from the condensation recovery module to enter the main heat exchange module and be discharged from the return air port of the device; if not, the third return air mode is executed, that is, the fifth pipeline is connected and the third pipeline and the fourth pipeline are disconnected, so that the fifth pipeline becomes the only cold air supply pipeline and allows the exhaust gas discharged from the outlet of the adsorption zone to enter the main heat exchange module and be discharged from the return air port of the device.

[0017] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects: According to the recovery and purification device and organic solvent recovery system provided by the present invention, when recovering and purifying low-boiling-point organic gas with large air volume and low concentration, the above-mentioned device and system are adjusted to the low-boiling-point treatment mode, that is, the first pipeline is connected and the second pipeline is disconnected at the same time, and the organic gas is recovered and purified by combining adsorption concentration by the adsorption rotor and condensation treatment by the condensation recovery module. When recovering and purifying high-boiling-point organic gas with large air volume and low concentration, the above-mentioned device and system are switched to the high-boiling-point treatment mode, at this time, the second pipeline is connected and the first pipeline is disconnected, and the organic gas is not adsorbed and concentrated by the adsorption rotor, but only by controlling the condensation temperature of the condensation recovery module to recover and purify the organic gas.

[0018] In this way, the recovery and processing mode can be flexibly adjusted according to the boiling point characteristics of the organic gas to be recovered, so that the recovery efficiency of the device and system for low-boiling-point organic gases and high-boiling-point organic gases can be improved to a certain extent. At the same time, it can also avoid the recovery and purification process of high-boiling-point organic gases from affecting the adsorption efficiency, capacity and selectivity of the adsorption wheel, thereby affecting the recovery and purification process of low-boiling-point organic gases, reducing the maintenance frequency of the device and improving the efficiency of continuous operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a structural schematic diagram of the recovery and purification device in Example 1; Figure 2 It is a structural schematic diagram of the recovery and purification device in Example 2; Figure 3 is a schematic structural diagram of an organic solvent recovery system in Example 1; Figure 4 is a schematic structural diagram of the organic solvent recovery system in Example 3; Figure 5 is a schematic structural diagram of an organic solvent recovery system in Example 4; Figure 6 is a schematic structural diagram of an organic solvent recovery system in Embodiment 5; Figure 7 is a flow chart of the mode control method in Embodiment 1; Figure 8It is a flow chart of the mode control method in the fifth embodiment.

[0021] Reference numerals 1. Main heat exchange module; 2. Condensation recovery module; 21. Cooling water condenser; 22. Chilled water condenser; 23. Antifreeze condenser; 3. Adsorption wheel; 31. Adsorption zone; 32. Cooling zone; 33. Regeneration zone; 4. Regeneration heater; 5. First pipeline; 51. First air valve; 52. Adsorption branch; 53. Regeneration branch; 54. Seventh air valve; 6. Second pipeline; 61. Second air valve; 7. Auxiliary heat exchange module ;8. Clean air exhaust pipeline;81. Main exhaust flow path;82. Air volume adjustment flow path;83. Sixth air valve;91. Third pipeline;911. Third air valve;92. Fourth pipeline;921. Fourth air valve;93. Fifth pipeline;931. Fifth air valve;10. Production equipment;100. Recovery and purification device;E1. Input port;E2. Output port;E3. Return air port;F1. External air source input port;101. Recovery system. DETAILED DESCRIPTION

[0022] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0023] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, 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 application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0024] 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 application, 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 this device and / or practice this method.

[0025] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being 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 complicated.

[0026] The embodiments of this specification propose a dual-mode organic gas recovery and purification device, an organic solvent recovery system and a mode control method, aiming to solve the problem that the VOC recovery and treatment equipment in the prior art cannot be used to treat both low-boiling point organic waste gas and high-boiling point organic waste gas, so that the recovery and purification device and the recovery system are not only suitable for treating low-boiling point organic waste gas, but also can achieve efficient recovery and purification of high-boiling point organic waste gas without increasing the regeneration energy consumption of the adsorption wheel, greatly expanding the scope of application and flexibility of the device.

[0027] The technical solutions provided by various embodiments of the present application are described below in conjunction with the accompanying drawings.

[0028] Embodiment 1 like Figure 1As shown, the dual-mode organic gas recovery and purification device has an input port E1, an output port E2 and a return air port E3. When the device is running, the organic gas to be recovered is input into the device from the input port E1 of the device for recovery and purification, and the clean gas is discharged from the output port E2 of the device. The return air port E3 of the device is suitable for connecting to the air inlet of the production equipment 10. At this time, the cold air after the heat exchange through the main heat exchange module 1 returns to the production equipment from the return air port E3. In some embodiments, the input port E1 of the device is connected to the exhaust port of the production equipment 10 that generates VOCs organic waste gas, such as coating and drying equipment, paint spraying equipment, lithium battery processing and manufacturing equipment, etc. In other embodiments, the input port E1 of the device can also be directly connected to the organic waste gas emission workshop, factory building, etc., which is not limited here. The organic compounds contained in the organic gas to be recovered may be aromatic hydrocarbons, ketones, ethers, etc. The organic gas may be a gas containing a single compound component, such as an organic gas containing trimethylol, whose boiling point is about 169°C, an organic gas containing octyl butyrate, whose boiling point is about 224°C, and an organic gas containing N-methylpyrrolidone (NMP), whose boiling point is about 202°C to 205°C. At this time, the boiling point of the organic gas refers to the boiling point of the organic compound contained in the gas. The organic gas may also be a gas containing multiple compound components, such as a mixed organic gas containing both N-methylpyrrolidone and octyl butyrate. The multiple compounds preferably have a narrow boiling point distribution range, so that common separation can be achieved through a single-stage condensation and / or adsorption process. At this time, the boiling point of the organic gas refers to the boiling point of the organic compound with the lowest boiling point temperature among the multiple organic compounds. It should be noted that the "connection" in this embodiment can mean direct connection, such as direct connection through a single pipe, or indirect connection, such as connection through a pipe valve assembly, and is not limited here.

[0029] In this embodiment, the dual-mode organic gas recovery and purification device 100 is configured to switch between a high boiling point treatment mode and a low boiling point treatment mode, and specifically includes a main heat exchange module 1, a cold air supply module, a condensation recovery module 2, an adsorption wheel 3, and a first pipeline 5 and a second pipeline 6, wherein the hot gas inlet of the main heat exchange module 1 is connected to the device input port E1, the air outlet of the cold air supply module is connected to the cold air inlet of the main heat exchange module, the air inlet of the condensation recovery module 2 is connected to the hot gas outlet of the main heat exchange module 1, and the adsorption wheel 3 includes at least an adsorption zone 31 and a regeneration zone 33, the outlet of the adsorption zone 31 is connected to the device output port E2, and the outlet of the regeneration zone 33 is connected to the air inlet of the condensation recovery module 2. The air inlets of the first pipeline 5 and the second pipeline 6 are both connected to the air outlet of the condensation recovery module 2, and the air outlet of the first pipeline 5 is connected to the inlet of the adsorption area 31. The second pipeline 6 bypasses the adsorption wheel 3 along the air flow direction and the pipeline air outlet is connected to the device output port E2. The first pipeline 5 and the second pipeline 6 are both controlled to be turned on or off and have mutually exclusive on-off states to facilitate the realization of different processing modes.

[0030] like Figure 1 and Figure 7 As shown, before the device is operated, it is first determined whether the organic gas to be treated is a high-boiling-point organic gas or a low-boiling-point organic gas, that is, whether the boiling point of the organic gas is higher than the temperature reference value or lower than the temperature reference value. If it is determined to be a low-boiling-point organic gas, the low-boiling-point treatment mode is executed while the device is operating, that is, the first pipeline 5 is connected and the second pipeline 6 is disconnected, and the organic gas is recovered and purified by combining adsorption concentration by the adsorption wheel 3 and condensation treatment by the condensation recovery module 2. If it is determined to be a high-boiling-point organic gas, the high-boiling-point treatment mode is executed while the device is operating, that is, the second pipeline 6 is connected and the first pipeline 5 is disconnected. At this time, the organic gas is not adsorbed and concentrated by the adsorption wheel 3, but is recovered and purified only by controlling the condensation temperature of the condensation recovery module 2. In this way, the recovery and processing mode is flexibly adjusted according to the boiling point characteristics of the organic gas to be recovered, so that the recovery efficiency of the device and system for low-boiling-point organic gases and high-boiling-point organic gases can be improved to a certain extent. At the same time, it can also avoid the recovery and purification process of high-boiling-point organic gases from affecting the adsorption efficiency, capacity and selectivity of the adsorption wheel 3, thereby affecting the recovery and purification process of low-boiling-point organic gases, reducing the maintenance frequency of the device and improving the efficiency of continuous operation of the device.

[0031] In this embodiment, multiple methods can be adopted to realize the on-off control of the first pipeline 5 and the second pipeline 6. As one embodiment, a first air valve 51 is provided on the first pipeline 5, and a second air valve 52 is provided on the second pipeline. The first air valve 51 and the second air valve 52 have mutually exclusive on-off states. As another embodiment, the air outlet of the condensation recovery module 2 is connected to the first pipeline 5 and the second pipeline 6 through a three-way valve (not shown in the figure). In this case, the air outlet of the condensation recovery module 2 can only be connected to one of the first pipeline 5 and the second pipeline 6. When the air outlet of the condensation recovery module 2 is connected to the first pipeline 5, the first pipeline 5 is in a conducting state and the second pipeline 6 is in a disconnected state. When the air outlet of the condensation recovery module 2 is connected to the second pipeline 6, the second pipeline 6 is in a conducting state and the first pipeline 5 is in a disconnected state. The setting of the three-way valve can simplify the pipeline structure, save design space, and reduce leakage points. However, the pressure loss is relatively large due to the complex valve flow path, and it cannot be applied to large flow path pipeline control. Technical personnel can select a suitable valve structure according to specific working conditions to achieve on-off control of the above-mentioned first pipeline 5 and the second pipeline 6, which will not be elaborated here.

[0032] like Figure 1 and Figure 2 As shown, in this embodiment, the adsorption rotor 3 includes an adsorption zone 31, a cooling zone 32 and a regeneration zone 33, the device also includes a regeneration heater 4, the first pipeline 5 is a Y-shaped structure with an air inlet and two air outlets, one end of which is connected to the condensation recovery module 2 and the other end is branched into an adsorption branch 52 and a regeneration branch 53, the air outlet of the adsorption branch 52 is connected to the adsorption zone 31 of the adsorption rotor 3, the air outlet of the regeneration branch 53 is connected to the regeneration zone 33 of the adsorption rotor 3, and the first air valve 51 is arranged on the main road of the first pipeline 5. The air outlet of the regeneration branch 53 is connected to the inlet of the cooling zone 32, the outlet of the cooling zone 32 is connected to the air inlet of the regeneration heater 4, and the air outlet of the regeneration heater 4 is connected to the inlet of the regeneration zone 33. When the device is in operation, part of the tail gas discharged from the condensation recovery module 2 passes through the first pipeline 5 to the adsorption zone 31 of the adsorption wheel for adsorption recovery and then is discharged from the output port E2 of the device, and part passes through the first pipeline 5 and the cooling zone 32 and then enters the regeneration heater 4 for high-temperature heating. The heated regeneration gas is sent to the regeneration zone 33 for desorption regeneration. The organic gas after desorption regeneration is mixed with the organic gas discharged from the main heat exchange module 1 and then re-enters the condensation recovery module 2 for condensation recovery. Preferably, the air inlet of the cooling zone 32 can also be connected to an external air source, so that the external air can also be used as a regeneration air source, and is preheated by passing through the relatively high-temperature cooling zone 32 before regeneration heating, thereby saving the working energy consumption of the regeneration heater.

[0033] In this embodiment, the main function of the main heat exchange module 1 in the recovery and purification device 100 is to exchange heat between the organic gas from the device input port E1 and the cold air supplied by the cold air supply module. The heat exchange efficiency of the main heat exchange module 1 can reach more than 90%. The specific form of the cold air supply module is described in detail below and will not be expanded here.

[0034] In this embodiment, the condensation recovery module 2 condenses and recovers the high-boiling-point organic gas from the main heat exchange module 1 in the high-boiling-point treatment mode, and condenses and recovers the mixed low-boiling-point organic gas from the main heat exchange module 1 and after concentration and regeneration by the adsorption wheel 3 in the low-boiling-point treatment mode. Here, the condensation recovery module 2 preferably adopts a step-by-step condensation method to cool the organic gas passing through in stages. Specifically, the condensation recovery module 2 includes a cooling water condenser, a chilled water condenser and an antifreeze liquid condenser that are sequentially connected along the air flow direction, wherein the cooling water condenser performs preliminary cooling and cooling of the organic gas after heat exchange with the main heat exchange module 1 to remove the remaining heat in the organic gas. At this stage, the outlet water temperature and the return water temperature of the cooling water pipeline are 32°C and 37°C, respectively. Then, the chilled water condenser uses low-temperature cold water to cool the organic gas. The organic gas is further cooled down. At this stage, most of the organic gas can be condensed and liquefied. The outlet water temperature and return water temperature of the chilled water pipeline are 7℃ and 12℃ respectively. The gas temperature of the organic gas can generally be reduced to 5℃~15℃. The antifreeze condenser, as the last stage cooling equipment, reduces the temperature of the organic gas from the chilled water condenser to -5℃~-10℃ to ensure that most of the organic compounds in the large air volume and low concentration organic gas can be condensed and recovered. The outlet water temperature and recovery temperature of the antifreeze pipeline are -20℃ and -15℃ respectively.

[0035] It should be noted that, since the saturated vapor pressure of high-boiling-point organic gases is relatively low, the method of condensing and recovering them through the condensation recovery module 2 not only has a higher recovery efficiency than the method of adsorption recovery using the adsorption rotor 3, but also has relatively low operating costs and equipment energy consumption because no regeneration heating is required. The saturated vapor pressure of low-boiling-point organic gases is relatively high and the concentration is low. At this time, if they are only condensed and recovered through the condensation recovery module 2, the energy consumption of the condensation recovery module 2 will be greatly increased due to the low condensation temperature required for complete recovery. The combination of condensation recovery and adsorption concentration by the adsorption rotor can not only improve the recovery efficiency, but also reduce the overall energy consumption of the recovery and purification device 100.

[0036] like Figure 3As shown, this embodiment also proposes an organic solvent recovery system 101, which is used to recover organic solvents from high-temperature exhaust gas containing organic solvents discharged from the production equipment 10. The recovery system includes the aforementioned dual-mode organic gas recovery and purification device 100, wherein the input port E1 of the recovery and purification device is connected to the exhaust port of the production equipment 10, and the return air port E3 of the recovery and purification device is connected to the air inlet of the production equipment 10.

[0037] Specifically, a circulating air supply pipeline is arranged between the return air port E3 of the device and the air inlet of the production equipment 10, and a first fan with an air volume adjustment function is arranged on the circulating air supply pipeline. An air inlet pipeline is arranged between the exhaust port of the production equipment 10 and the device input port E1, and a second fan with an air volume adjustment function is arranged on the air inlet pipeline. The internal wind pressure and air volume of the production equipment 10 can be adjusted through the cooperation of the first fan and the second fan.

[0038] In one embodiment, the exhaust volume of the production equipment 10 is 12000-15000 Nm 3 / h, temperature 170 ° C, the concentration of organic solvent trimethylol is 2000 ~ 2500ppm, at this time the device is in the low boiling point treatment mode, the exhaust gas of the production equipment 10 enters the main heat exchange module 1 from the device input port E1 for heat exchange, the temperature of the discharged organic gas a is 15 ~ 20 ° C, the organic gas a is mixed with the organic gas b after desorption and regeneration in the regeneration zone 33 and enters the condensation recovery module 2 for condensation recovery, the organic gas c that is not condensed and liquefied after passing through the condensation recovery module 2, partially enters the adsorption zone 31 for adsorption purification, the purified tail gas d is discharged from the device output port E2, the exhaust volume of the tail gas d is 2000 ~ 2500Nm 3 / h, part of it passes through the cooling zone 32 and then enters the regeneration heater 4 for regeneration heating. The temperature of the regeneration gas f after regeneration heating is 160-170°C, and the temperature of the organic gas b after desorption and regeneration in the regeneration zone 33 is 60-65°C.

[0039] In addition, in order to more clearly and completely reveal the inventive concept of this solution, this embodiment also proposes a mode control method of the dual-mode organic gas recovery and purification device 100, such as Figure 7 As shown, the method comprises the following steps: S1. Compare the boiling point temperature of the current organic gas to be treated with the set temperature reference value. If it is lower than the temperature reference value, execute S2-1; if it is higher than the temperature reference value, execute S2-2. In some embodiments, the setting of the temperature reference value is related to the operating conditions of the condensation recovery module 2. For example, the lower the condensation temperature at which the condensation recovery module 2 can operate, the lower the temperature reference value can be adjusted accordingly, and vice versa.

[0040] In one embodiment, the temperature reference value can be set to 180°C. When the organic gas to be treated is an organic gas containing only trimethylol, since its boiling point is lower than 180°C, S2-1 is executed. When the organic gas to be treated is an organic gas containing only octyl butyrate, its boiling point is about 224°C, and the boiling point is higher than 180°C, S2-2 is executed.

[0041] S2-1, operate the device and execute the low boiling point treatment mode, specifically, the first pipeline 5 is turned on and the second pipeline 6 is turned off, so as to allow the organic gas discharged through the condensation recovery module 2 to enter the adsorption zone 31 and the cooling zone 32 of the adsorption wheel 3 from the first pipeline 5, while preventing the tail gas discharged through the condensation recovery module 2 from entering the output port E2 of the device from the second pipeline 6. At this time, at least part of the organic gas flows from the device input port E1 through the main heat exchange module 1, the condensation recovery module 2, the first pipeline 5, the adsorption zone 31 of the adsorption wheel 3 to the device output port E2. In this embodiment, in the low boiling point treatment mode, the first air valve 51 is turned on and the second air valve 61 is turned off.

[0042] S2-2, operate the device and execute the high boiling point treatment mode, specifically, the second pipeline 6 is turned on and the first pipeline 5 is turned off, so as to allow the organic gas discharged through the condensation recovery module 2 to enter the output port E2 of the device from the second pipeline 6, while preventing the tail gas discharged through the condensation recovery module 2 from entering the adsorption zone 31 and the cooling zone 32 of the adsorption wheel 3 from the first pipeline 5. At this time, at least part of the organic gas flows from the device input port E1 through the main heat exchange module 1, the condensation recovery module 2, the second pipeline 6 to the device output port E2. In this embodiment, in the high boiling point treatment mode, the second air valve 61 is turned on and the first air valve 51 is turned off.

[0043] The similarity between the low boiling point treatment mode in S2-1 and the high boiling point treatment mode in S2-2 is that the organic gas to be treated input from the device input port E1 needs to be sequentially heat exchanged through the main heat exchange module 1 and condensed and recovered through the condensation recovery module 2. The difference between the two is that in the low boiling point treatment mode, the remaining tail gas discharged from the outlet of the condensation recovery module 2 does not meet the emission standard and needs to be further treated. At this time, part of the gas in the remaining tail gas is adsorbed and purified by the adsorption zone 31 of the adsorption wheel 3 and then discharged from the device output port E2, and part of the gas enters the regeneration zone 33 through the cooling zone 32 for desorption and regeneration. The organic gas after desorption and regeneration is mixed with the organic gas discharged from the outlet of the main heat exchange module 1 and then re-enters the condensation recovery module 2 for condensation and recovery. In the high boiling point treatment mode, the tail gas discharged from the outlet of the condensation recovery module 2 has reached the emission standard, and does not need to be further treated at this time, and can be directly discharged, so it can be directly transported from the second pipeline 6 to the device output port E2 for discharge.

[0044] By dividing the organic gas to be treated into high-boiling point organic gas and low-boiling point organic gas, and providing corresponding treatment modes for organic gases with different boiling point characteristics, the recovery and purification device 100 has a higher comprehensive recovery efficiency for organic gas. At the same time, it can avoid the treatment process of high-boiling point gas from affecting or interfering with the treatment process of low-boiling point gas, thereby reducing the maintenance frequency of the device and improving the efficiency of continuous operation of the device.

[0045] Embodiment 2 The basic structure of this embodiment is the same as that of the first embodiment. The difference between the two is that in this embodiment, Figure 2 As shown, it also includes a clean gas discharge pipeline 8 and an auxiliary heat exchange module 7. The hot gas inlet of the auxiliary heat exchange module 7 is connected to the outlet of the regeneration zone 33, and the hot gas outlet of the auxiliary heat exchange module 7 is connected to the air inlet of the condensation recovery module 2. The auxiliary heat exchange module 7 performs heat exchange between the regenerated high-temperature organic gas and its cold flow, and pre-cools the regenerated high-temperature organic gas before it re-enters the condensation recovery module 2, thereby reducing the use of chilled water and the working energy consumption of the condensation recovery module 2. Here, the cold air source of the auxiliary heat exchange module 7 has various forms, including but not limited to a gas cold source or a liquid cold source, which is not limited here.

[0046] Preferably, the cold air inlet of the auxiliary heat exchange module 7 is connected to the outlet of the adsorption zone 31, and the cold air outlet of the auxiliary heat exchange module 7 is connected to the device output port E2. In this way, the low-temperature tail gas discharged from the device output port E2 can be used to exchange heat with the regenerated gas, which not only realizes the pre-cooling of the high-temperature organic gas, but also reduces the dependence of the heat exchange equipment on the external cold source. The clean air discharge pipeline 8 includes a main exhaust flow path 81 and an air volume regulating flow path 82, wherein the air inlet of the main exhaust flow path 81 is connected to the outlet of the adsorption zone 31 and the air outlet of the second pipeline 6, the air outlet of the main exhaust flow path 81 is connected to the cold air inlet of the auxiliary heat exchange module 7, the air outlet of the air volume regulating flow path 82 is connected to the device output port E2 and the air inlet is connected to the main exhaust flow path 81, and the air volume regulating flow path 82 is provided with a sixth air valve 83 for adjusting the cold air volume entering the auxiliary heat exchange module 7. Preferably, an exhaust fan is also provided on the main exhaust flow path 81 .

[0047] Embodiment 3 The basic structure of this embodiment is the same as that of the first embodiment, and the difference between the two is that Figure 4As shown, the cold air supply module includes a third pipeline 91, the air inlet of the third pipeline 91 is connected to the external air source input port F1 for fresh air to enter, and the air outlet of the third pipeline 91 is connected to the cold air inlet of the main heat exchange module 1. The third pipeline 91 is provided with a third air valve 911 to control the conduction or disconnection of the third pipeline 91. Here, the source of fresh air is preferably workshop air intake.

[0048] In one embodiment, the exhaust volume of the production equipment 10 is 15000 Nm 3 / h, the fresh air supply reaches 94% of the air intake of the production equipment. The fresh air is used as the cold air source of the main heat exchange module 1 and as the main air supply source of the production equipment 10. The advantage is that the air supply is highly pure and has no effect on the production process in the production equipment 10. However, this also means that most of the clean exhaust gas discharged from the device output port E2 is not used, resulting in energy waste.

[0049] Embodiment 4 The basic structure of this embodiment is the same as that of the first embodiment, and the difference between the two is that Figure 5 As shown, in the cold air supply module, fresh air is not used as the cold source of the main heat exchange module 1 and the air supply source of the production equipment 10, but the return air in the device is used as the cold source of the main heat exchange module 1 and the air supply source of the production equipment 10. Specifically, the cold air supply module includes a fourth pipeline 92 and a fifth pipeline 93, both of which have air outlets connected to the cold air inlet of the main heat exchange module 1, the air inlet of the fourth pipeline 92 is connected to the air outlet of the condensation recovery module 2, and the air inlet of the fifth pipeline 93 is connected to the outlet of the adsorption wheel adsorption area 31. The fourth pipeline 92 and the fifth pipeline 93 are both controlled to be turned on or off and have mutually exclusive on-off states.

[0050] When the fourth pipeline 92 is in conduction, the fifth pipeline 93 is disconnected. At this time, most of the exhaust gas discharged from the condensation recovery module 2 enters the main heat exchange module 1 through the fourth pipeline 92, exchanges heat with the organic gas input to the device, and then returns to the production equipment 10. The advantage of adopting the above-mentioned return air after the condensation recovery module 2 is that the amount of exhaust gas that needs to be purified by the rotor is small, usually less than 6% of the total amount of organic gas input, which greatly reduces the size of the rotor, reduces equipment investment, and reduces the regeneration energy consumption of the rotor by about 90%. In addition, the low-temperature gas after cooling returns to the main heat exchange module 1, which can reduce the gas temperature at the hot gas outlet by about 30°C, reduce the use of chilled water in the subsequent condensation recovery module 2, and save energy by at least 80%. The disadvantage is that in the low boiling point treatment mode, the return air still contains a small amount of organic compounds. As the gas supply source of the equipment, it may cause the concentration in the production equipment 10 to increase, thereby affecting production.

[0051] When the fifth pipeline 93 is in conduction, the fourth pipeline 92 is disconnected. At this time, most of the exhaust gas discharged from the adsorption zone 31 of the adsorption wheel 3 enters the main heat exchange module 1 through the fifth pipeline 93, exchanges heat with the organic gas of the input device, and then returns to the production equipment 10. The advantage of adopting the above-mentioned method of returning air after the rotor is that the return air has a high purity and has little effect on the solvent concentration in the production equipment. The low-temperature gas after the rotor treatment returns to the main heat exchange module 1, which can reduce the temperature of the hot gas outlet gas by about 27.9°C and reduce the use of chilled water. The disadvantage is that the entire amount of exhaust air needs to be purified by the rotor, the regeneration energy consumption of the rotor increases, and the equipment investment is large.

[0052] In this embodiment, a fourth air valve 921 is provided on the fourth pipeline 92, and a fifth air valve 931 is provided on the fifth pipeline 93. The fourth air valve 921 and the fifth air valve 931 have mutually exclusive on-off states, and the fourth air valve 921 and the fifth air valve 931 are configured to be independent of the first pipeline 5 and the second pipeline 6, so that their on-off states will not interfere with the on-off states of the first pipeline 5 and the second pipeline 6.

[0053] Embodiment 5 The basic structure of this embodiment is the same as that of the first embodiment, and the difference between the two is that Figure 6 As shown, the cold air supply module includes a third pipeline 91, a fourth pipeline 92 and a fifth pipeline 93, and the air outlets of the three are connected to the cold air inlet of the main heat exchange module 1. The air inlet of the third pipeline 91 is used for fresh air, the air inlet of the fourth pipeline 92 is connected to the air outlet of the condensation recovery module 2, and the air inlet of the fifth pipeline 93 is connected to the outlet of the adsorption area 31. The third pipeline 91, the fourth pipeline 92 and the fifth pipeline 93 are all controlled to be turned on or off and when one of the pipelines is turned on, the other two pipelines are disconnected.

[0054] In this embodiment, a third air valve 911 is provided on the third pipeline 91, a fourth air valve 921 is provided on the fourth pipeline 92, and a fifth air valve 931 is provided on the fifth pipeline 93. When one of the third air valve 911, the fourth air valve 921 and the fifth air valve 931 is turned on, the other two are in a disconnected state, and the third air valve 911, the fourth air valve 921 and the fifth air valve 931 are configured to be independent of the first pipeline 5 and the second pipeline 6, so that their on-off states will not interfere with the on-off states of the first pipeline 5 and the second pipeline 6.

[0055] like Figure 8 As shown, based on the arrangement of the cold air supply module, this embodiment further improves the mode control method of the recovery and purification device 100 described in the first embodiment, that is, while the device described in S2-1 is running, the following steps are added: Determine whether the current working condition can execute the first return air mode. If yes, execute the first return air mode, that is, turn on the third air valve 911 and disconnect the fourth air valve 921 and the fifth air valve 931, so that the third pipeline 911 becomes the only cold air supply pipeline and allows fresh air to enter the main heat exchange module 1 and be discharged from the return air port E3 of the device. At this time, the fresh air enters the main heat exchange module 1 through the third pipeline 91 to perform heat exchange with the organic gas from the device input port E1, and then returns to the production equipment 10 through the return air port E3; if no, execute the next step; Determine whether the current working condition can execute the second return air mode, that is, turn on the fourth air valve 921 and disconnect the third air valve 911 and the fifth air valve 931 at the same time, so that the fourth pipeline 921 becomes the only cold air supply pipeline and allows the tail gas discharged from the condensation recovery module 2 to enter the main heat exchange module 1 and be discharged from the return air port E3 of the device. At this time, most of the tail gas from the condensation recovery module 2 enters the main heat exchange module 1 through the fourth pipeline 92 to exchange heat with the organic gas from the device input port E1, and then returns to the production equipment 10 through the return air port E3; if not, execute the next step; The third return air mode is executed, that is, the fifth air valve 931 is turned on and the third air valve 911 and the fourth air valve 921 are disconnected at the same time, so that the fifth pipeline 931 becomes the only cold air supply pipeline and allows the exhaust gas discharged from the outlet of the adsorption zone 31 to enter the main heat exchange module 1 and be discharged from the return air port E3 of the device. At this time, at least part of the clean exhaust gas from the adsorption zone 31 enters the main heat exchange module 1 via the fourth pipeline 92 to exchange heat with the organic gas from the device input port E1, and then returns to the production equipment 10.

[0056] While the device in S2-2 is running, the following steps are also performed: Determine whether the current working condition can execute the first return air mode. If yes, execute the first return air mode, that is, turn on the third air valve 911 and disconnect the fourth air valve 921 and the fifth air valve 931, so that the third pipeline 911 becomes the only cold air supply pipeline and allows fresh air to enter the main heat exchange module 1 and be discharged from the return air port E3 of the device. At this time, the fresh air enters the main heat exchange module 1 through the third pipeline 91 to perform heat exchange with the organic gas from the device input port E1, and then returns to the production equipment 10; if no, execute the next step; The second return air mode is executed, that is, the fourth air valve 921 is turned on and the third air valve 911 and the fifth air valve 931 are disconnected at the same time, so that the fourth pipeline 921 becomes the only cold air supply pipeline and allows the exhaust gas discharged from the condensation recovery module 2 to enter the main heat exchange module 1 and be discharged from the return air port E3 of the device. At this time, most of the exhaust gas from the condensation recovery module 2 enters the main heat exchange module 1 through the fourth pipeline 92 to exchange heat with the organic gas from the device input port E1, and then returns to the production equipment 10.

[0057] It has been learned from the third and fourth embodiments that the first return air mode preferentially uses workshop air intake, which has the advantage of high purity of the gas returned to the production equipment 10 and no effect on the production process in the production equipment 10. The second return air mode requires less exhaust gas to be purified by the rotary wheel. The third return air mode has a higher return air purity, which has little effect on the solvent concentration in the production equipment and has high energy utilization, but the entire exhaust air needs to be purified by the rotary wheel. In this embodiment, three return air modes are provided for users to choose from, so that the recovery system 101 can better adapt to the on-site working conditions, thereby increasing the adaptability and flexibility of the above-mentioned recovery and purification device and system when applied.

[0058] Preferably, a seventh air valve 54 is further provided on the connecting pipeline between the regeneration zone 33 and the auxiliary heat exchange module 7. The seventh air valve 54 is a one-way valve and has the same on-off state as the first air valve 51. The setting of the seventh air valve 54 can prevent the backflow of desorbed and regenerated organic gas when the device stops operating, causing cross contamination.

[0059] In summary, in the above embodiments, the recovery and purification device 100 and the organic solvent recovery system 101 can flexibly adjust the recovery and processing mode according to the boiling point characteristics of the organic gas to be recovered, so that the recovery efficiency of the device and the system for low-boiling-point organic gases and high-boiling-point organic gases can be improved to a certain extent. At the same time, it can also avoid the recovery and purification process of high-boiling-point organic gases from affecting the adsorption efficiency, capacity and selectivity of the adsorption wheel, and then affecting the recovery and purification process of low-boiling-point organic gases, thereby reducing the maintenance frequency of the device and improving the efficiency of continuous operation of the device.

[0060] In this specification, the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the embodiments described later, the description is relatively simple, and the relevant parts can be referred to the partial description of the previous embodiments.

[0061] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A dual-mode organic gas recovery and purification device, configured to switch between a high boiling point treatment mode and a low boiling point treatment mode, characterized in that: include: Input, output and return air vents; A main heat exchange module, whose hot air inlet is connected to the input port, and whose cold air outlet is connected to the return air port; A cold air supply module, the air outlet of which is connected to the cold air inlet of the main heat exchange module; A condensation recovery module, the air inlet of which is connected to the hot air outlet of the main heat exchange module; an adsorption rotor, comprising at least an adsorption zone and a regeneration zone, wherein the outlet of the adsorption zone is connected to the output port, and the outlet of the regeneration zone is connected to the air inlet of the condensation recovery module; and The first pipeline and the second pipeline, both of which have air inlets connected to the air outlet of the condensation recovery module, and the air outlet of the first pipeline is connected to the inlet of the adsorption zone, and the second pipeline bypasses the adsorption wheel along the air flow direction and the pipeline outlet is connected to the device output port; The first pipeline and the second pipeline are both controlled to be turned on or off and have mutually exclusive on-off states so as to realize different processing modes.

2. The dual-mode organic gas recovery and purification device according to claim 1, characterized in that: The cold air supply module comprises: The third pipeline has an air inlet for fresh air to enter, and an air outlet thereof is connected to the cold air inlet of the main heat exchange module.

3. The dual-mode organic gas recovery and purification device according to claim 1, characterized in that: The cold air supply module comprises: The air outlets of the fourth pipeline and the fifth pipeline are both connected to the cold air inlet of the main heat exchange module, the air inlet of the fourth pipeline is connected to the air outlet of the condensation recovery module, and the air inlet of the fifth pipeline is connected to the outlet of the adsorption zone of the adsorption wheel; The fourth pipeline and the fifth pipeline are both controlled to be turned on or off and have mutually exclusive on-off states.

4. The dual-mode organic gas recovery and purification device according to claim 1, characterized in that: The cold air supply module comprises: The air outlets of the third pipeline, the fourth pipeline and the fifth pipeline are all connected to the cold air inlet of the main heat exchange module, the air inlet of the third pipeline is for fresh air to enter, the air inlet of the fourth pipeline is connected to the air outlet of the condensation recovery module, and the air inlet of the fifth pipeline is connected to the outlet of the adsorption zone; The third pipeline, the fourth pipeline and the fifth pipeline are all controlled to be turned on or off, and when one pipeline is turned on, the other two pipelines are turned off.

5. The dual-mode organic gas recovery and purification device according to claim 1, characterized in that: It also includes an auxiliary heat exchange module, the hot gas inlet of the auxiliary heat exchange module is connected to the outlet of the regeneration zone, and the hot gas outlet of the auxiliary heat exchange module is connected to the air inlet of the condensation recovery module.

6. The dual-mode organic gas recovery and purification device according to claim 5, characterized in that: The cold air inlet of the auxiliary heat exchange module is communicated with the outlet of the adsorption zone, and the cold air outlet of the auxiliary heat exchange module is communicated with the device output port.

7. The dual-mode organic gas recovery and purification device according to claim 1, characterized in that: The adsorption wheel also includes a cooling zone and a regeneration heater, the air inlet of the cooling zone is connected to the external air source and / or the air outlet of the first pipeline, the air inlet of the regeneration heater is connected to the air outlet of the cooling zone, and the air outlet of the regeneration heater is connected to the inlet of the regeneration zone.

8. An organic solvent recovery system, used to recover organic solvents from high-temperature tail gas containing organic solvents discharged from production equipment, characterized in that: The recovery system comprises a dual-mode organic gas recovery and purification device as described in any one of claims 1 to 7, wherein the input port of the recovery and purification device is connected to the exhaust port of the production equipment, and the return air port of the recovery and purification device is connected to the air inlet of the production equipment.

9. The mode control method of the dual-mode organic gas recovery and purification device according to claim 7, characterized in that: The method comprises the following steps: S1, compare the boiling point temperature of the organic gas to be processed with the set temperature reference value, if it is lower than the temperature reference value, execute S2-1, if it is higher than the temperature reference value, execute S2-2; S2-1, operating the device and executing the low boiling point treatment mode, specifically, connecting the first pipeline and disconnecting the second pipeline, thereby allowing the organic gas discharged through the condensation recovery module to enter the adsorption zone and cooling zone of the adsorption wheel from the first pipeline, while preventing the tail gas discharged through the condensation recovery module from entering the output port of the device from the second pipeline; S2-2, operate the device and execute the high boiling point treatment mode, specifically, connect the second pipeline and disconnect the first pipeline, thereby allowing the organic gas discharged through the condensation recovery module to enter the output port of the device from the second pipeline while preventing the exhaust gas discharged through the condensation recovery module from entering the adsorption zone and cooling zone of the adsorption wheel from the first pipeline.

10. The mode control method according to claim 9, characterized in that: In S2-1, while the device is running, it is determined whether the current working condition allows the execution of the first return air mode. If so, the first return air mode is executed, that is, the third pipeline is connected and the fourth pipeline and the fifth pipeline are disconnected, so that the third pipeline becomes the only cold air supply pipeline and allows fresh air to enter the main heat exchange module and be discharged from the return air port of the device; If not, it is determined whether the current working condition allows the execution of the second return air mode. If so, the second return air mode is executed, that is, the fourth pipeline is connected and the third pipeline and the fifth pipeline are disconnected, so that the fourth pipeline becomes the only cold air supply pipeline and the tail gas discharged from the condensation recovery module is allowed to enter the main heat exchange module and be discharged from the return air port of the device; Otherwise, the third return air mode is executed, that is, the fifth pipeline is turned on and the third pipeline and the fourth pipeline are disconnected, so that the fifth pipeline becomes the only cold air supply pipeline and allows the exhaust gas discharged from the outlet of the adsorption zone to enter the main heat exchange module and be discharged from the return air outlet of the device.

Images