Heat pump of coating and recycling all-in-one machine

Abstract

The utility model belongs to the technical field of lithium battery production, and particularly provides a coating and recycling all-in-one machine heat pump which comprises a coating drying oven, a gas-gas heat exchanger used for conducting heat exchange on high-temperature gas and low-temperature gas, a tail gas treatment device used for treating tail gas and an NMP waste liquid temporary storage tank used for storing liquid. High-temperature gas in the coating oven is guided into a high-temperature area of the gas-gas heat exchanger through the exhaust fan, and low-temperature gas cooled by the refrigerant low-temperature heat exchanger set is guided into a low-temperature area through the air return fan. And the gas subjected to heat exchange and temperature returning through the gas-gas heat exchanger is guided into the heating medium high-temperature heat exchanger group through the air return fan to be heated and then is guided into the coating oven again. According to the utility model, a refrigerant, a heating medium and gas are adopted for direct heat exchange, the efficiency is higher, meanwhile, the air temperature can be heated to be more than 130 DEG C, the requirements of high-temperature heating places of the coating oven are met, the original electric heating and steam heating processes are replaced, and the real energy-saving target is realized.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery production technology, and specifically to a coating and recycling integrated heat pump. Background Technology

[0002] The coating process of the positive electrode coating machine generates a large amount of high-temperature waste gas containing volatile organic compounds such as NMP (methylpyrrolidone). Because NMP is valuable and harmful to the environment, the NMP waste gas needs to be recovered. The current popular treatment process for NMP recovery systems is: waste heat recovery (gas-to-gas heat exchange) + condensation + 95% return air + 5% rotary wheel treatment before discharge. The condensation section and the rotary wheel section require 7~12℃ low-temperature chilled water, which needs to be provided by the customer's refrigeration unit.

[0003] During operation, the positive electrode coating machine needs to heat the oven to dry the coated battery electrode sheets. The oven can be heated by electric heating, steam heating generated by burning natural gas, or heating by heat transfer oil.

[0004] For existing cascade heat pump unit processes, hot water can generally only be heated to around 85°C, with the highest experimental temperature reaching only 125°C. In addition, heating of the coating oven and NMP condensation recovery are achieved by producing chilled water and high-temperature hot water. When the heat on the high-temperature side arrives but the cooling capacity on the low-temperature side does not, there is an imbalance between heat supply and demand. At this time, it is necessary to add an auxiliary refrigeration unit to further reduce the condensation temperature. Utility Model Content

[0005] To address the technical problems in the existing technology, this utility model provides a coating and recycling integrated heat pump, including a coating oven, a gas-to-gas heat exchanger for exchanging heat between high-temperature gas and low-temperature gas, a tail gas treatment device for treating tail gas, and an NMP waste liquid temporary storage tank for storing liquid. It also includes a refrigerant low-temperature heat exchanger group and a heat medium high-temperature heat exchanger group. The refrigerant low-temperature heat exchanger group is connected to the gas-to-gas heat exchanger, and the heat medium high-temperature heat exchanger group is installed between the gas-to-gas heat exchanger and the coating oven. The high-temperature gas in the coating oven is introduced into the high-temperature zone of the gas-to-gas heat exchanger by an exhaust fan. The low-temperature gas after dehumidification and condensation by the refrigerant low-temperature heat exchanger group is introduced into the low-temperature zone of the gas-to-gas heat exchanger by a return air fan. The gas that has been heated back by heat exchange in the gas-to-gas heat exchanger is introduced into the heat medium high-temperature heat exchanger group by the return air fan for reheating and then reintroduced into the coating oven.

[0006] Furthermore, a medium-efficiency filter is installed between the coating oven and the high-temperature heat exchanger assembly.

[0007] Furthermore, the refrigerant cryogenic heat exchanger assembly includes a refrigerant cryogenic heat exchanger, an expansion valve, a cryogenic compressor, a plate heat exchanger B, and multiple refrigerant pipelines. The air inlet of the refrigerant cryogenic heat exchanger is connected to the high-temperature zone of the gas-gas heat exchanger, and the air outlet of the refrigerant cryogenic heat exchanger is connected to the low-temperature zone of the gas-gas heat exchanger. The liquid outlet of the refrigerant cryogenic heat exchanger is connected to the NMP waste liquid temporary storage tank. The refrigerant cryogenic heat exchanger is also provided with port a and port d, and port a is located at the end near the air inlet of the refrigerant cryogenic heat exchanger. The plate heat exchanger B is provided with port b and port c. Port a is connected to port b through refrigerant pipelines and the cryogenic compressor, and port c is connected to port d through refrigerant pipelines and the expansion valve.

[0008] Furthermore, the high-temperature heat exchanger assembly includes a high-temperature heat exchanger, an expansion valve, a high-temperature compressor, a plate heat exchanger A, and multiple heat exchanger pipelines. The air inlet of the high-temperature heat exchanger is connected to the low-temperature zone of the gas-to-gas heat exchanger, and the air outlet of the high-temperature heat exchanger is connected to the coating oven through a medium-efficiency filter. The high-temperature heat exchanger is provided with an f port and a g port, and the g port is located near the air inlet of the high-temperature heat exchanger. The plate heat exchanger A is provided with an e port and an h port. The g port is connected to the h port through the heat exchanger pipeline and the expansion valve, and the e port is connected to the f port through the heat exchanger pipeline and the high-temperature compressor.

[0009] Furthermore, a balance adjustment device for realizing the conversion of cold and heat is installed between the plate heat exchanger A and the plate heat exchanger B.

[0010] Furthermore, the balancing and regulating device includes a buffer water tank and an internal circulating water pump. The outlet of the plate heat exchanger A is connected to the first inlet of the buffer water tank, and the first outlet of the buffer water tank is connected to the inlet of the plate heat exchanger B through the internal circulating water pump. The outlet of the plate heat exchanger B is connected to the inlet of the plate heat exchanger A. The water temperature in the buffer water tank is maintained at a set value. Under the action of the internal circulating water pump, the cold energy absorbed by the plate heat exchanger A and the heat generated by the plate heat exchanger B are converted through the buffer water tank.

[0011] Furthermore, the balance adjustment device also includes electric valve A, electric valve B, a cooling tower, and a circulating water pump. The second outlet of the buffer water tank is connected to the inlet of the cooling tower through electric valve B, and the outlet of the cooling tower is connected to the second inlet of the buffer water tank through the circulating water pump and electric valve A. The buffer water tank is equipped with an electric heating module. When the water temperature in the buffer water tank is lower than the set value, the electric heating module is turned on, and electric valve A, electric valve B, and the circulating water pump are turned off. When the water temperature in the buffer water tank is higher than the set value, electric valve A, electric valve B, and the circulating water pump are turned on, and the electric heating module is turned off.

[0012] Furthermore, the set value is 50℃~60℃.

[0013] Beneficial effects:

[0014] 1. In this utility model, by setting up a low-temperature heat exchanger group for refrigerant and a high-temperature heat exchanger group for heat medium, direct heat exchange between refrigerant, heat medium and gas is adopted, which is more efficient. At the same time, the air temperature can be heated to above 130℃, which meets the needs of high-temperature heating places in coating ovens, replaces the original electric heating and steam heating processes, and achieves the goal of true energy saving.

[0015] 2. In this utility model, the medium-efficiency filter can filter the gas heated by the high-temperature heat exchanger assembly; the low-temperature heat exchanger, expansion valve, low-temperature compressor, plate heat exchanger B, and multiple refrigerant pipelines can transport low-temperature refrigerant to the high-temperature zone of the low-temperature heat exchanger and the gas-to-gas heat exchanger for heat exchange, reducing the condensation temperature to about 15°C and achieving NMP condensation recovery; the high-temperature heat exchanger, expansion valve, high-temperature compressor, plate heat exchanger A, and multiple heat exchanger pipelines can transport high-temperature heat medium to the high-temperature heat exchanger, allowing the 104°C air from the low-temperature zone of the gas-to-gas heat exchanger to be reheated, raising the temperature to over 130°C.

[0016] 3. In this utility model, by setting up a balance adjustment device including a buffer water tank and an internal circulating water pump, the heat generated by the low-temperature compressor can be transferred to the high-temperature compressor, and the cold energy absorbed by the high-temperature compressor can be transferred to the low-temperature compressor, thus ensuring the balance and stability of the high-temperature compressor and the low-temperature compressor.

[0017] 4. In this utility model, by setting up electric valve A, electric valve B, cooling water tower, circulating water pump and electric heating module, the water temperature in the buffer tank can be maintained at the set value, and the supply and demand balance of cooling and heating can be adjusted, so that the low temperature compressor can continuously cool and lower the low temperature side temperature of the low temperature compressor, while simultaneously enabling the high temperature compressor to continuously heat and raise the high temperature side temperature of the high temperature compressor to the set value, thereby achieving energy-saving and stable operation, wherein the set value is 50℃~60℃;

[0018] When the specific equipment system starts up and runs, the internal circulating water pump is turned on, the water temperature in the buffer tank is maintained at the set value, and electric valves A and B and the circulating water pump are turned off.

[0019] When the water temperature in the buffer tank exceeds the upper limit of the set value, electric valve A, electric valve B and circulating water pump open, and electric heating module closes, cooling and heat dissipation are achieved through cooling tower;

[0020] When the water temperature in the buffer tank is lower than the lower limit of the set value, the electric heating module is turned on, and electric valve A, electric valve B and circulating water pump are turned off. In actual use, the electric heating module is generally only activated when the water temperature in the buffer tank is too low during the initial start-up. During normal operation, the temperature rises rapidly, so even if the temperature is lower than the lower limit of the set value, the electric heating module is also in the off state.

[0021] The specific process is as follows:

[0022] When the water temperature in the buffer tank exceeds 60°C, the system will open electric valves A and B and the circulating water pump, allowing the cooling water circulating in the cooling tower to enter the buffer tank for heat exchange and cooling. When the water temperature in the buffer tank drops below 50°C, the system will automatically close electric valves A and B and the circulating water pump, stopping the cooling water from cooling the buffer tank. When the water temperature rises slowly and is below 50°C, the electric heating module in the buffer tank will be turned on. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0025] Figure 2 This is a schematic diagram of the installation structure of the refrigerant low-temperature heat exchanger group, the heat medium high-temperature heat exchanger group, and the balance adjustment device of this utility model.

[0026] In the picture:

[0027] 1. Coating oven; 2. Gas-to-gas heat exchanger; 3. Exhaust gas treatment device; 4. NMP waste liquid temporary storage tank; 5. Exhaust fan; 6. Return air fan; 7. Medium-efficiency filter; 8. Refrigerant low-temperature heat exchanger; 9. Expansion valve; 10. Low-temperature compressor; 11. Plate heat exchanger B; 12. Heat medium high-temperature heat exchanger; 13. High-temperature compressor; 14. Plate heat exchanger A; 15. Buffer water tank; 16. Internal circulating water pump; 17. Electric valve A; 18. Electric valve B; 19. Cooling tower; 20. Circulating water pump. Detailed Implementation

[0028] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0029] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0032] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0034] This utility model provides a heat pump for an integrated coating and recycling machine, such as... Figure 1 As shown, the system includes a coating oven 1, a gas-to-gas heat exchanger 2 for exchanging heat between high-temperature and low-temperature gases, a tail gas treatment device 3 for treating exhaust gas, and an NMP waste liquid temporary storage tank 4 for storing liquid. It also includes a refrigerant low-temperature heat exchanger group and a heat medium high-temperature heat exchanger group. The refrigerant low-temperature heat exchanger group is connected to the gas-to-gas heat exchanger 2, and the heat medium high-temperature heat exchanger group is installed between the gas-to-gas heat exchanger 2 and the coating oven 1. The high-temperature gas in the coating oven 1 is introduced into the high-temperature zone of the gas-to-gas heat exchanger 2 by an exhaust fan 5, while the refrigerant low-temperature gas... After dehumidification and condensation, the low-temperature gas from the heat exchanger group is introduced into the low-temperature zone of the gas-to-gas heat exchanger 2 through the return air fan 6. After heat exchange and reheating in the gas-to-gas heat exchanger 2, the gas is introduced into the high-temperature heat exchanger group of the heat medium through the return air fan 6 for reheating and then reintroduced into the coating oven 1. In actual production, the low-temperature heat exchanger group of the refrigerant, the high-temperature heat exchanger group of the heat medium, the gas-to-gas heat exchanger 2, the exhaust fan 5, and the return air fan 6 are integrated together and made into a whole unit using steel frame and sheet metal, which is convenient for installation and transportation. On-site installation only requires pipe connection.

[0035] In this embodiment, by setting up a low-temperature heat exchanger group for refrigerant and a high-temperature heat exchanger group for heat medium, direct heat exchange between refrigerant, heat medium and gas is adopted, which is more efficient. At the same time, the air temperature can be heated to above 130°C to meet the needs of the high-temperature heating environment of the coating oven 1, replacing the original electric heating and steam heating processes and achieving a true energy-saving goal.

[0036] In this utility model, preferably, such as Figure 1 As shown, a medium-efficiency filter 7 is installed between the coating oven 1 and the high-temperature heat exchanger assembly.

[0037] In this embodiment, the medium-efficiency filter 7 can be used to filter the gas after it has been heated by the high-temperature heat exchanger assembly.

[0038] In this utility model, preferably, such as Figure 1 and Figure 2As shown, the refrigerant low-temperature heat exchanger assembly includes a refrigerant low-temperature heat exchanger 8, an expansion valve 9, a low-temperature compressor 10, a plate heat exchanger B11, and multiple refrigerant pipelines. The air inlet of the refrigerant low-temperature heat exchanger 8 is connected to the high-temperature zone of the gas-to-gas heat exchanger 2, and the air outlet of the refrigerant low-temperature heat exchanger 8 is connected to the low-temperature zone of the gas-to-gas heat exchanger 2. The drain outlet of the refrigerant low-temperature heat exchanger 8 is connected to the NMP waste liquid storage tank 4. The refrigerant low-temperature heat exchanger 8 is also provided with port a and port d, and port a is located near the air inlet of the refrigerant low-temperature heat exchanger 8. The plate heat exchanger B11 is provided with port b and port c. Port a is connected to port b via a refrigerant pipeline and a cryogenic compressor 10. Port c is connected to port d via a refrigerant pipeline and an expansion valve 9. The flow direction is as follows: from port a, through the cryogenic compressor 10 to port b; from port c of the plate heat exchanger B11, through the expansion valve 9 to port d and into the refrigerant cryogenic heat exchanger 8. The temperature at port d drops to approximately 3°C. Since port d is located near the air outlet of the refrigerant cryogenic heat exchanger 8, and the cryogenic refrigerant and gas flow in opposite directions, the heat conversion efficiency can be improved, ensuring that the air temperature exiting the air outlet of the refrigerant cryogenic heat exchanger 8 is effectively reduced. The temperature can be as low as around 15°C. The high-temperature heat exchanger assembly includes a high-temperature heat exchanger 12, an expansion valve 9, a high-temperature compressor 13, a plate heat exchanger A14, and multiple heat medium pipelines. The air inlet of the high-temperature heat exchanger 12 is connected to the low-temperature zone of the gas-to-gas heat exchanger 2, and the air outlet of the high-temperature heat exchanger 12 is connected to the coating oven 1 through a medium-efficiency filter 7. The high-temperature heat exchanger 12 is equipped with an f port and a g port, with the g port located near the air inlet of the high-temperature heat exchanger 12. The plate heat exchanger A14 is equipped with an e port and an h port, and the g port is connected to the expansion valve 9 through the heat medium pipelines and the expansion valve 9. The expansion valve 9 is connected to port h. Port e is connected to port f through the heat medium pipeline and high-temperature compressor 13. Its flow direction is from port g through the expansion valve 9 to port h. After exiting port e of plate heat exchanger A14, it passes through high-temperature compressor 13 to port f and enters heat medium high-temperature heat exchanger 12. The temperature at port f rises to about 140°C. Since port f is located near the air outlet of heat medium high-temperature heat exchanger 12 and the high-temperature heat medium and gas flow in opposite directions, the heat conversion efficiency can be improved, ensuring that the air temperature coming out of the air outlet of heat medium high-temperature heat exchanger 12 is effectively raised to about 130°C.

[0039] In this embodiment, through the arrangement of the refrigerant low-temperature heat exchanger 8, expansion valve 9, low-temperature compressor 10, plate heat exchanger B11, and multiple refrigerant pipelines, low-temperature refrigerant can be transported to the high-temperature zone of the refrigerant low-temperature heat exchanger 8 and the 35°C air coming out of the gas-to-gas heat exchanger 2 for heat exchange, thereby reducing the condensation temperature to about 15°C and realizing the condensation recovery of NMP; through the arrangement of the heat medium high-temperature heat exchanger 12, expansion valve 9, high-temperature compressor 13, plate heat exchanger A14, and multiple heat medium pipelines, high-temperature heat medium can be transported to the heat medium high-temperature heat exchanger 12, thereby reheating the 104°C air coming out of the low-temperature zone of the gas-to-gas heat exchanger 2, raising the temperature to above 130°C;

[0040] The operating principles of the refrigerant low-temperature heat exchanger group and the heat medium high-temperature heat exchanger group are as follows:

[0041] like Figure 1 and Figure 2 As shown, ⓐ the working fluid is in a low-temperature, low-pressure gas state; ⓑ the gaseous working fluid is compressed by the compressor into a high-temperature, high-pressure gas; ⓒ the high-temperature, high-pressure gaseous working fluid releases heat through a phase change in the condenser under constant pressure, becoming a high-pressure liquid state; ⓓ the high-pressure liquid working fluid is depressurized and cooled by the expansion valve 9, becoming a low-temperature, low-pressure gas-liquid mixture state; ⓔ the low-temperature, low-pressure gas-liquid mixture absorbs heat from the outside through the evaporator, becoming a low-temperature, low-pressure gas state; ⓕ the gaseous working fluid is compressed by the compressor into a high-temperature, high-pressure gas; ⓖ the high-temperature, high-pressure gaseous working fluid releases heat through a phase change in the condenser under constant pressure, becoming a high-pressure liquid state; ⓗ the high-pressure liquid working fluid is depressurized and cooled by the expansion valve 9, becoming a low-pressure gas-liquid mixture state.

[0042] In this utility model, preferably, such as Figure 1 and Figure 2 As shown, a balancing device for achieving the conversion of cooling and heating is installed between plate heat exchanger A14 and plate heat exchanger B11. The balancing device includes a buffer tank 15 and an internal circulating water pump 16. The outlet of plate heat exchanger A14 is connected to the first inlet of buffer tank 15, and the first outlet of buffer tank 15 is connected to the inlet of plate heat exchanger B11 via internal circulating water pump 16. The outlet of plate heat exchanger B11 is connected to the inlet of plate heat exchanger A14. The water temperature in buffer tank 15 is maintained at a set value. Under the action of the internal circulating water pump 16, the cold energy absorbed by the plate heat exchanger A14 and the heat generated by the plate heat exchanger B11 are converted through the buffer water tank 15. The outlet end of the plate heat exchanger A14 is close to port h, the inlet end of the plate heat exchanger A14 is close to port e, the inlet end of the plate heat exchanger B11 is close to port c, and the outlet end of the plate heat exchanger B11 is close to port b. Through the above arrangement, the flow direction in the heat medium pipeline, the cold medium pipeline and the water circulation pipeline can be reversed, thereby improving the heat conversion efficiency.

[0043] In this embodiment, by setting up a balance adjustment device including a buffer water tank 15 and an internal circulating water pump 16, the heat generated by the low-temperature compressor 10 can be transferred to the high-temperature compressor 13, and the cold energy absorbed by the high-temperature compressor 13 can be transferred to the low-temperature compressor 10, ensuring the balance and stability of the high-temperature compressor 13 and the low-temperature compressor 10.

[0044] In this utility model, preferably, such as Figure 1 and Figure 2 As shown, the balance adjustment device also includes electric valve A17, electric valve B18, cooling tower 19, and circulating water pump 20. The second outlet of the buffer water tank 15 is connected to the inlet of the cooling tower 19 through electric valve B18. The outlet of the cooling tower 19 is connected to the second inlet of the buffer water tank 15 through the circulating water pump 20 and electric valve A17. The buffer water tank 15 is equipped with an electric heating module. When the water temperature in the buffer water tank 15 is lower than the set value, the electric heating module is turned on, and electric valve A17, electric valve B18, and circulating water pump 20 are turned off. When the water temperature in the buffer water tank 15 is higher than the set value, electric valve A17, electric valve B18, and circulating water pump 20 are turned on, and the electric heating module is turned off. In addition, other cooling circulating water pipelines can be set between the cooling tower 19 and electric valves A17 and B18 to other cooling terminal equipment. The set value is 50℃~60℃.

[0045] In this embodiment, by setting up electric valve A17, electric valve B18, cooling tower 19, circulating water pump 20 and electric heating module, the water temperature in buffer tank 15 can be maintained at a set value, and the supply and demand balance of cooling and heating can be adjusted, so that low temperature compressor 10 can continuously cool and the low temperature side temperature of low temperature compressor 10 is lowered. At the same time, high temperature compressor 13 can continuously heat and the high temperature side temperature of high temperature compressor 13 is raised to a set value, so as to achieve energy-saving and stable operation, wherein the set value is 50℃~60℃.

[0046] When the specific equipment system is started and running, the internal circulating water pump 16 is turned on, the water temperature in the buffer water tank 15 is maintained at the set value, and the electric valves A17 and B18 and the circulating water pump 20 are turned off.

[0047] When the water temperature in the buffer tank 15 exceeds the upper limit of the set value, the electric valve A17, the electric valve B18 and the circulating water pump 20 are opened, and the electric heating module is turned off, so that the cooling tower 19 can be used to cool down and dissipate heat.

[0048] When the water temperature in the buffer tank 15 is lower than the lower limit of the set value, the electric heating module is turned on, and the electric valve A17, electric valve B18 and circulating water pump 20 are turned off. In actual use, the electric heating module is generally only activated when the machine is turned on for the first time because the temperature in the buffer tank 15 is too low. During normal operation, the temperature rises quickly, so even if the temperature is lower than the lower limit of the set value, the electric heating module is also in the off state.

[0049] The specific process is as follows:

[0050] When the water temperature in the buffer tank 15 is higher than 60℃, the system will open electric valve A17, electric valve B18 and circulating water pump 20, so that the cooling circulating water in the cooling tower 19 enters the buffer tank 15 through the circulating water pump 20 for heat exchange and cooling. When the water temperature in the buffer tank 15 drops below 50℃, the system will automatically close electric valve A17, electric valve B18 and circulating water pump 20, and stop the cooling of the buffer tank 15 by the cooling circulating water. When the water temperature rises slowly and is below 50℃, the electric heating module in the buffer tank 15 will be turned on.

[0051] Working principle:

[0052] like Figure 1 and Figure 2 As shown, the high-temperature exhaust gas (approximately 120°C) containing over 35% NMP from the coating oven 1 is extracted by the exhaust fan 5. It first enters the gas-to-gas heat exchanger 2 (high-efficiency waste heat recovery, heat exchange efficiency approximately 80%), where it exchanges heat with the condensed low-temperature return air (approximately 15°C). The high-temperature exhaust gas then drops to approximately 35°C. Next, it passes through a refrigerant low-temperature heat exchanger group, where the exhaust air exchanges heat with the low-temperature refrigerant and condenses, further reducing the temperature to approximately 15°C. At this point, the NMP has condensed, and the NMP concentration in the exhaust gas has decreased from 2500 PPM to 300 PPM, meeting the return air process conditions for dehumidification and cooling. After condensation, 90% to 95% of the air at around 15°C passes through the gas-to-gas heat exchanger 2 (high-efficiency waste heat recovery, heat exchange efficiency of about 80%) to exchange heat with the high-temperature exhaust gas at around 120°C from the coating dehumidification process. The remaining air is discharged through the exhaust gas treatment device 3. After heat exchange, the temperature rises to around 104°C. Then, it passes through the high-temperature heat exchanger group of the heat medium, where the temperature rises to over 130°C. After being filtered by the medium-efficiency filter 7, it is sent to the return air inlet of the coating oven 1 by the return air fan 6. During the above process, the waste liquid generated by the gas-to-gas heat exchanger 2, the low-temperature heat exchanger group of the refrigerant, and the exhaust gas treatment device 3 is discharged into the NMP waste liquid temporary storage tank 4.

[0053] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A coating and recycling integrated heat pump, comprising a coating oven (1), a gas-to-gas heat exchanger (2) for exchanging heat between high-temperature gas and low-temperature gas, a tail gas treatment device (3) for treating tail gas, and an NMP waste liquid temporary storage tank (4) for storing liquid, characterized in that, It also includes a refrigerant low-temperature heat exchanger group and a heat medium high-temperature heat exchanger group. The refrigerant low-temperature heat exchanger group is connected to the gas-to-gas heat exchanger (2). The heat medium high-temperature heat exchanger group is installed between the gas-to-gas heat exchanger (2) and the coating oven (1). The high-temperature gas in the coating oven (1) is introduced into the high-temperature zone of the gas-to-gas heat exchanger (2) by the exhaust fan (5). The low-temperature gas after dehumidification and condensation by the refrigerant low-temperature heat exchanger group is introduced into the low-temperature zone of the gas-to-gas heat exchanger (2) by the return air fan (6). After the gas-to-gas heat exchanger (2) is heated and warmed up, the gas is introduced into the heat medium high-temperature heat exchanger group by the return air fan (6) for reheating and then reintroduced into the coating oven (1).

2. The heat pump for an integrated coating and recycling machine according to claim 1, characterized in that, A medium-efficiency filter (7) is installed between the coating oven (1) and the high-temperature heat exchanger assembly.

3. A coating and recycling integrated heat pump according to claim 1 or 2, characterized in that, The refrigerant low-temperature heat exchanger assembly includes a refrigerant low-temperature heat exchanger (8), an expansion valve (9), a low-temperature compressor (10), a plate heat exchanger B (11), and multiple refrigerant pipelines. The air inlet of the refrigerant low-temperature heat exchanger (8) is connected to the high-temperature zone of the gas-gas heat exchanger (2), and the air outlet of the refrigerant low-temperature heat exchanger (8) is connected to the low-temperature zone of the gas-gas heat exchanger (2). The drain outlet of the refrigerant low-temperature heat exchanger (8) is connected to the NMP waste liquid storage tank (4). The refrigerant low-temperature heat exchanger (8) is also provided with port a and port d, and port a is located near the air inlet of the refrigerant low-temperature heat exchanger (8). The plate heat exchanger B (11) is provided with port b and port c. Port a is connected to port b through the refrigerant pipeline and the low-temperature compressor (10), and port c is connected to port d through the refrigerant pipeline and the expansion valve (9).

4. The heat pump for an integrated coating and recycling machine according to claim 3, characterized in that, The heat exchanger assembly includes a heat exchanger (12), an expansion valve (9), a high-temperature compressor (13), a plate heat exchanger A (14), and multiple heat exchanger pipelines. The air inlet of the heat exchanger (12) is connected to the low-temperature zone of the gas-gas heat exchanger (2), and the air outlet of the heat exchanger (12) is connected to the coating oven (1) through a medium-efficiency filter (7). The heat exchanger (12) is provided with an f port and a g port, and the g port is located near the air inlet of the heat exchanger (12). The plate heat exchanger A (14) is provided with an e port and an h port. The g port is connected to the h port through the heat exchanger pipeline and the expansion valve (9), and the e port is connected to the f port through the heat exchanger pipeline and the high-temperature compressor (13).

5. A coating and recycling integrated heat pump according to claim 4, characterized in that, A balance adjustment device for realizing the conversion of cold and heat is installed between the plate heat exchanger A (14) and the plate heat exchanger B (11).

6. The heat pump for an integrated coating and recycling machine according to claim 5, characterized in that, The balance adjustment device includes a buffer water tank (15) and an internal circulation water pump (16). The outlet of the plate heat exchanger A (14) is connected to the first inlet of the buffer water tank (15). The first outlet of the buffer water tank (15) is connected to the inlet of the plate heat exchanger B (11) through the internal circulation water pump (16). The outlet of the plate heat exchanger B (11) is connected to the inlet of the plate heat exchanger A (14). The water temperature in the buffer water tank (15) is maintained at a set value. Under the action of the internal circulation water pump (16), the cold energy absorbed by the plate heat exchanger A (14) and the heat generated by the plate heat exchanger B (11) are converted through the buffer water tank (15).

7. A coating and recycling integrated heat pump according to claim 6, characterized in that, The balance adjustment device also includes electric valve A (17), electric valve B (18), cooling tower (19) and circulating water pump (20). The second outlet of the buffer tank (15) is connected to the inlet of the cooling tower (19) through electric valve B (18). The outlet of the cooling tower (19) is connected to the second inlet of the buffer tank (15) through circulating water pump (20) and electric valve A (17). The buffer tank (15) is equipped with an electric heating module. When the water temperature in the buffer tank (15) is lower than the set value, the electric heating module is turned on and the electric valve A (17), electric valve B (18) and circulating water pump (20) are turned off. When the water temperature in the buffer tank (15) is higher than the set value, the electric valve A (17), electric valve B (18) and circulating water pump (20) are turned on and the electric heating module is turned off.

8. The heat pump for an integrated coating and recycling machine according to claim 7, characterized in that, The set value is 50℃~60℃.

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