Multi-stage ultralow-temperature dehumidification circulating treatment system and operation method thereof

Abstract

The invention provides a multi-stage ultralow-temperature dehumidification circulating treatment system and an operation method thereof, and the multi-stage ultralow-temperature dehumidification circulating treatment system comprises a dryer, a gas-gas heat exchanger, a low-temperature evaporation module, at least one stage of ultralow-temperature evaporation module, a low-temperature heat exchange module, at least one stage of ultralow-temperature heat exchange module, an electric auxiliary heater and a circulating fan, the low-temperature evaporation module comprises at least two low-temperature evaporators which are switched by low-temperature valve banks to form alternate operation, and the ultralow-temperature evaporation module comprises at least two ultralow-temperature evaporators which are switched by ultralow-temperature valve banks to form alternate operation; the low-temperature heat exchange module comprises a low-temperature preheater and a low-temperature heater, and the ultralow-temperature heat exchange module comprises an ultralow-temperature preheater and an ultralow-temperature heater; the dryer, the gas-gas heat exchanger, the low-temperature evaporation module, the ultralow-temperature evaporation module, the ultralow-temperature preheater, the low-temperature preheater, the gas-gas heat exchanger, the low-temperature heater, the ultralow-temperature heater, the electric auxiliary heater, the circulating fan and the dryer are sequentially connected to form a drying circulation loop.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchange, and relates to a drying and dehumidification system, in particular to a multi-stage ultra-low temperature dehumidification circulation treatment system and an operation method thereof. Background Art

[0002] A high-temperature dryer is a dryer that uses high-temperature technology. The working principle of the existing dryer is as follows: (1) Compression process: The low-temperature and low-pressure refrigerant gas is compressed by the compressor into a high-temperature and high-pressure gas. At this time, the work done by the compressor is converted into the internal energy of the refrigerant gas, causing its temperature and pressure to increase. This is called an adiabatic process in thermodynamics. (2) Condensation process: The high-temperature and high-pressure refrigerant gas from the compressor flows through the condenser and continuously releases heat to the outside world by wind or water, condensing into a medium-temperature and high-pressure refrigerant liquid. During liquefaction, the refrigerant temperature decreases but the pressure remains unchanged. This is called an isobaric process in thermodynamics. (3) Throttling process: The medium-temperature and high-pressure refrigerant liquid from the condenser is throttled by the throttling device and becomes a low-temperature and low-pressure refrigerant liquid. This is called an isenthalpic process in thermodynamics. (4) Evaporation process: The low-temperature and low-pressure refrigerant liquid from the throttling device flows through the evaporator and continuously absorbs heat from the room by wind or water, evaporating into a low-temperature and low-pressure refrigerant gas. The absorbed heat becomes the latent heat of the refrigerant. Although the temperature does not rise much, the internal energy increases a lot. Since the pressure does not change much, it is called an isobaric process in thermodynamics.

[0003] The common high-temperature drying technology currently used will cause changes in the properties of some drying objects, which will have an irreversible impact on product quality. Low-temperature drying technology is slow and inefficient, and the results it can achieve are not ideal. Therefore, it is necessary to develop a new type of low-temperature drying technology. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems in the prior art and to propose a multi-stage ultra-low temperature dehumidification cycle treatment system and its operation method.

[0005] The object of the present invention can be achieved through the following technical solutions: a multi-stage ultra-low temperature dehumidification circulation treatment system, comprising a dryer, an air-to-air heat exchanger, a low-temperature evaporation module, at least one level of ultra-low temperature evaporation module, a low-temperature heat exchange module, at least one level of ultra-low temperature heat exchange module, an electric auxiliary heater and a circulating fan, characterized in that the low-temperature evaporation module comprises at least two low-temperature evaporators, at least two low-temperature evaporators are switched by a low-temperature valve group to form alternating operation, the ultra-low temperature evaporation module comprises at least two ultra-low temperature evaporators, at least two ultra-low temperature evaporators are switched by an ultra-low temperature valve group to form alternating operation; the low-temperature heat exchange module comprises a low-temperature preheater and a low-temperature heater, and the ultra-low temperature heat exchange module comprises an ultra-low temperature preheater and an ultra-low temperature heater; the dryer, the air-to-air heat exchanger, the low-temperature evaporation module, the ultra-low temperature evaporation module, the ultra-low temperature preheater, the low-temperature preheater, the air-to-air heat exchanger, the low-temperature heater, the ultra-low temperature heater, the electric auxiliary heater, the circulating fan and the dryer are connected in sequence to form a drying circulation loop.

[0006] Preferably, the low-temperature heat exchange module further includes a low-temperature return air solenoid valve, a low-temperature compressor, a low-temperature condenser, a low-temperature liquid reservoir, a low-temperature liquid supply solenoid valve and a low-temperature expansion valve, and the low-temperature evaporator, the low-temperature return air solenoid valve, the low-temperature compressor, the low-temperature heater, the low-temperature condenser, the low-temperature liquid reservoir, the low-temperature preheater, the low-temperature liquid supply solenoid valve, the low-temperature expansion valve and the low-temperature evaporator are connected in sequence to form a low-temperature heat exchange circulation loop;

[0007] The ultra-low temperature heat exchange module also includes an ultra-low temperature return air solenoid valve, an ultra-low temperature compressor, an ultra-low temperature condenser, an ultra-low temperature liquid reservoir, an ultra-low temperature liquid supply solenoid valve and an ultra-low temperature expansion valve. The ultra-low temperature evaporator, the ultra-low temperature return air solenoid valve, the ultra-low temperature compressor, the ultra-low temperature heater, the ultra-low temperature condenser, the ultra-low temperature liquid reservoir, the ultra-low temperature preheater, the ultra-low temperature liquid supply solenoid valve, the ultra-low temperature expansion valve and the ultra-low temperature evaporator are connected in sequence to form an ultra-low temperature heat exchange circulation loop.

[0008] Preferably, the low-temperature valve group includes a low-temperature air inlet valve connected to the inlet of the low-temperature evaporator, and a low-temperature air outlet valve connected to the outlet of the low-temperature evaporator, and a low-temperature drain port is provided at the bottom of the low-temperature evaporator;

[0009] The ultra-low temperature valve group includes an ultra-low temperature air inlet valve connected to the inlet of the ultra-low temperature evaporator, and an ultra-low temperature air outlet valve connected to the outlet of the ultra-low temperature evaporator. An ultra-low temperature drain port is arranged at the bottom of the ultra-low temperature evaporator.

[0010] An operation method of a multi-stage ultra-low temperature dehumidification cycle treatment system comprises the following steps:

[0011] S1. Place the workpiece in the dryer, start the circulating fan to blow high-temperature dry hot air into the dryer to dehumidify the workpiece; during the drying process, the high-humidity air flows out of the dryer and enters the air-to-air heat exchanger. After the sensible heat exchange is completed, the moisture content and temperature of the high-humidity air are reduced by one level to form a first-level cooling airflow, and the condensed water is discharged from the air-to-air heat exchanger;

[0012] S2, the first-stage cooling airflow flows out of the air-to-air heat exchanger and enters one of the low-temperature evaporators of the low-temperature evaporation module. After the currently working low-temperature evaporator is frosted, the low-temperature valve group switches to other low-temperature evaporators, and the frosted low-temperature evaporator is defrosted; after the first-stage cooling airflow undergoes heat and moisture exchange, the moisture content is reduced by one level, and the temperature is reduced by one level to form a second-stage cooling airflow, and the condensed water is discharged from the low-temperature evaporator;

[0013] S3, the secondary cooling airflow flows out of the low-temperature evaporation module and enters one of the ultra-low temperature evaporators of the ultra-low temperature evaporation module. After the ultra-low temperature evaporator currently working is frosted, the ultra-low temperature valve group switches to other ultra-low temperature evaporators, and the frosted ultra-low temperature evaporator is defrosted; after the secondary cooling airflow undergoes heat and moisture exchange, the moisture content is reduced by one level, and the temperature is reduced by one level to form a third-level cooling airflow, and the condensed water is discharged from the ultra-low temperature evaporator;

[0014] S4, the three-stage cooling airflow flows out of the ultra-low temperature evaporation module and enters the ultra-low temperature preheater. The three-stage cooling airflow absorbs heat through the ultra-low temperature preheater, and the temperature is increased by one level, the moisture content remains unchanged, and the relative humidity is reduced by one level, forming a first-stage warming airflow; the first-stage warming airflow flows out of the ultra-low temperature preheater and enters the low temperature preheater. The first-stage warming airflow absorbs heat through the low temperature preheater, and the temperature is increased by one level, the moisture content remains unchanged, and the relative humidity is reduced by one level, forming a second-stage warming airflow;

[0015] S5, the secondary warming airflow flows out of the low-temperature preheater and enters the air-to-air heat exchanger, and the secondary warming airflow exchanges heat and moisture with the high-humidity air, the temperature rises by one level, the moisture content remains unchanged, and the relative humidity decreases by one level, forming a tertiary warming airflow;

[0016] S6, the three-stage warming airflow flows out of the air-to-air heat exchanger and enters the low-temperature heater, the three-stage warming airflow exchanges heat with the high-temperature exhaust gas, the temperature increases by one level, the moisture content remains unchanged, and the relative humidity decreases by one level, forming a four-stage warming airflow; the four-stage warming airflow flows out of the low-temperature heater and enters the ultra-low-temperature heater, the four-stage warming airflow exchanges heat with the high-temperature exhaust gas, the temperature increases by one level, the moisture content remains unchanged, and the relative humidity decreases by one level, forming a five-stage warming airflow;

[0017] S7, the five-stage heated airflow flows out of the ultra-low temperature heater and enters the electric auxiliary heater. The five-stage heated airflow is electrically heated, the temperature is increased by one level, the moisture content remains unchanged, and the relative humidity is reduced by one level, forming a six-stage heated airflow; the six-stage heated airflow is pressurized by the circulating fan and enters the dryer again for dehumidification.

[0018] Preferably, in step S2, the air temperature in the low-temperature evaporator is controlled in the range of -5°C to -20°C, and the corresponding evaporation temperature range is -10°C to -25°C; the moisture content of the secondary cooling airflow ranges from 2.3 to 0.6 g / kg;

[0019] In step S3, the air temperature range in the ultra-low temperature evaporator is controlled at -40°C to -60°C, and the corresponding evaporation temperature range is -45°C to -65°C; the moisture content of the three-stage cooling airflow reaches below 0.1g / kg, and the relative humidity is 95%.

[0020] Preferably, in step S5, the temperature of the secondary heated airflow entering the gas-to-gas heat exchanger is above 0°C.

[0021] Preferably, in step S7, when the temperature of the electric auxiliary heater is controlled to be 40°C, the relative humidity of the outlet air of the electric auxiliary heater is not higher than 0.2%; the moisture content of the sixth-stage heated airflow reaches below 0.1 g / kg, and the relative humidity is 0.2%.

[0022] Preferably, the low-temperature and low-pressure gaseous refrigerant flows out of the low-temperature evaporator and enters the low-temperature compressor through the low-temperature return gas solenoid valve. The low-temperature compressor discharges the high-temperature and high-pressure gaseous refrigerant and enters the low-temperature heater to complete heat exchange. The temperature of the gaseous refrigerant is reduced and enters the low-temperature condenser for condensation. The condensed high-temperature liquid refrigerant enters the low-temperature liquid storage device and then enters the low-temperature preheater for heat exchange. The temperature of the liquid refrigerant is reduced to complete supercooling. The supercooled liquid refrigerant passes through the low-temperature liquid supply solenoid valve and enters the low-temperature expansion valve for throttling. The throttled low-temperature and low-pressure liquid refrigerant enters the low-temperature evaporator to absorb heat and evaporate to become a low-temperature and low-pressure gaseous refrigerant.

[0023] The low-temperature and low-pressure gaseous refrigerant flows out of the ultra-low-temperature evaporator and enters the ultra-low-temperature compressor through the ultra-low-temperature return gas solenoid valve. The ultra-low-temperature compressor discharges the high-temperature and high-pressure gaseous refrigerant and enters the ultra-low-temperature heater to complete the heat exchange. The temperature of the gaseous refrigerant is reduced and enters the ultra-low-temperature condenser for condensation. The condensed high-temperature liquid refrigerant enters the ultra-low-temperature liquid storage device and then enters the ultra-low-temperature preheater for heat exchange. The temperature of the liquid refrigerant is reduced to complete supercooling. The supercooled liquid refrigerant passes through the ultra-low-temperature liquid supply solenoid valve and enters the ultra-low-temperature expansion valve for throttling. The low-temperature and low-pressure liquid refrigerant after throttling enters the ultra-low-temperature evaporator to absorb heat and evaporate into a low-temperature and low-pressure gaseous refrigerant.

[0024] Preferably, at least one low-temperature temperature sensor is provided in the low-temperature evaporator, and the air temperature range in the low-temperature evaporator is -5 to -20°C;

[0025] At least one ultra-low temperature sensor is arranged in the ultra-low temperature evaporator, and the air temperature range in the ultra-low temperature evaporator is -40 to -60°C.

[0026] Preferably, after one of the low-temperature evaporators in the low-temperature evaporation module has been running for 4 to 6 hours cumulatively, the low-temperature evaporator enters the defrosting process, and another low-temperature evaporator is switched to start operation; at least one defrosting temperature sensor is arranged in the low-temperature evaporator, and when the defrosting temperature of the low-temperature evaporator is lower than the defrosting switching temperature, the low-temperature evaporator enters the defrosting process, and another low-temperature evaporator is switched to start operation; the defrosting switching temperature is the refrigeration shutdown temperature of the low-temperature evaporator minus 8 to 15°C;

[0027] After one of the ultra-low temperature evaporators in the ultra-low temperature evaporation module has run for a total of 8 to 10 hours, the ultra-low temperature evaporator enters the defrost process and switches to another ultra-low temperature evaporator to start operation; at least one defrost temperature sensor is arranged in the ultra-low temperature evaporator, and when the defrost temperature of the ultra-low temperature evaporator is lower than the defrost switching temperature, the ultra-low temperature evaporator enters the defrost process and switches to another ultra-low temperature evaporator to start operation; the defrost switching temperature is the ultra-low temperature evaporator refrigeration shutdown temperature minus 8 to 15°C.

[0028] The defrost switching adopts a dual control logic that combines time control with defrost switching temperature control. When the system operation reaches any of these conditions, the two evaporators will switch. The control logic of the low temperature stage and the ultra-low temperature stage is the same.

[0029] Compared with the prior art, the multi-stage ultra-low temperature dehumidification cycle treatment system and its operation method have the following beneficial effects:

[0030] 1. The present invention adopts ultra-low humidity air for low-temperature drying, and realizes ultra-low humidity air treatment through two-stage or even multi-stage ultra-low temperature evaporation and wet heat exchange, thereby accelerating the drying process, and the dried material can reach a lower water content, thereby improving the dehumidification efficiency and drying effect.

[0031] 2. The present invention uses at least two evaporators in the same-level evaporation module to perform rotation switching operation, thereby achieving continuity of cooling and dehumidification, automatically sensing the degree of frost on the evaporator, automatically switching to the standby evaporator for operation, and using a variety of methods to promptly remove frost to avoid the impact of frost on the cooling effect of the evaporator and prevent intermittent shutdown of the overall dehumidification operation. The rotation mechanism cooperates with intermittent defrosting to ensure that the cooling process is not interrupted, the system can operate stably for a long time, and reduce maintenance and downtime.

[0032] 3. The various heat exchange devices in the system have greatly improved energy efficiency through effective heat recovery and reuse. The cross-structure heat exchange arrangement enables the airflow at each stage to achieve optimal temperature and humidity control, and fully utilizes the cycle conversion of thermal energy, reducing energy waste and improving overall energy efficiency.

[0033] 4. The temperature sensor and defrost temperature sensor in the system can monitor the working status of each evaporator in real time. When the temperature reaches the preset range, the automatic control system adjusts the refrigeration and defrost process to ensure that each evaporator operates at the most suitable working temperature. This precise temperature control mechanism not only ensures the stability and efficiency of the system, but also effectively avoids damage to the evaporator due to overcooling or overheating.

[0034] 5. Both low-temperature and ultra-low-temperature evaporators are equipped with defrost temperature sensors. According to the working time and temperature changes of the evaporator, the system can automatically determine whether to enter the defrost process. When the evaporator working time accumulates to a certain length of time or the temperature conditions meet the defrost conditions, the system will automatically switch to the standby evaporator and perform defrost operations. This flexible defrost control method enables the system to operate continuously and efficiently, and reduces the risk of reduced cooling efficiency or equipment failure due to frosting.

[0035] 6. By controlling the temperature of the electric auxiliary heater, the temperature of the airflow can be adjusted according to the needs of different materials to ensure the final drying effect. This control mechanism enables the system to be widely used in a variety of different drying demand scenarios, especially in high-precision processes with strict requirements on temperature and humidity, showing extremely high adaptability.

[0036] 7. Due to the use of dual evaporator rotation and automatic defrost control mechanism, the system can run continuously for a long time, avoiding the shutdown problem of traditional equipment caused by evaporator frosting or temperature instability. This high-reliability design effectively reduces the maintenance frequency and maintenance cost, improves the operating efficiency of the equipment, and is suitable for long-term uninterrupted working environment.

[0037] 8. The multi-stage heat exchange and refrigerant circuit design in the system optimizes the utilization efficiency of the refrigerant and reduces energy consumption. At the same time, the temperature is adjusted and controlled by the electric auxiliary heater, avoiding the high-energy heating process, reducing the overall energy consumption, meeting the requirements of modern environmental protection and energy saving, and having high market competitiveness.

[0038] In summary, the present invention achieves efficient dehumidification while ensuring the stability, energy saving, flexibility and efficiency of the system through technical means such as multi-stage ultra-low temperature evaporation, wet heat exchange, and heat recovery, and has significant technical advantages and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the structure of the multi-stage ultra-low temperature dehumidification cycle treatment system.

[0040] In the figure, 1, dryer; 2, air-to-air heat exchanger; 3, heat exchange drain; 4, low-temperature evaporator 1; 5, low-temperature evaporator 2; 6, low-temperature drain 1; 7, low-temperature drain 2; 8, ultra-low-temperature evaporator 1; 9, ultra-low-temperature evaporator 2; 10, ultra-low-temperature drain 1; 11, ultra-low-temperature drain 2; 12, ultra-low-temperature preheater; 13, low-temperature preheater; 14, low-temperature heater; 15, ultra-low-temperature heater; 16, electric auxiliary heater; 17, circulating fan; 18, low-temperature compressor; 19, low-temperature condenser; 20, low-temperature liquid storage; 21, low-temperature liquid supply solenoid valve 1; 22, low-temperature expansion valve 1; 23, low-temperature return gas solenoid valve 1; 2 4. Low-temperature liquid supply solenoid valve 2; 25. Low-temperature expansion valve 2; 26. Low-temperature return air solenoid valve 2; 27. Ultra-low temperature compressor; 28. Ultra-low temperature condenser; 29. ​​Ultra-low temperature liquid storage device; 30. Ultra-low temperature liquid supply solenoid valve 1; 31. Ultra-low temperature expansion valve 1; 32. Ultra-low temperature return air solenoid valve 1; 33. Ultra-low temperature liquid supply solenoid valve 2; 34. Ultra-low temperature expansion valve 2; 35. Ultra-low temperature return air solenoid valve 2; 36. Low-temperature air inlet valve 1; 37. Low-temperature air inlet valve 2; 38. Low-temperature air outlet valve 1; 39. Low-temperature air outlet valve 2; 40. Ultra-low temperature air inlet valve 1; 41. Ultra-low temperature air inlet valve 2; 42. Ultra-low temperature air outlet valve 1; 43. Ultra-low temperature air outlet valve 2. DETAILED DESCRIPTION

[0041] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0042] like Figure 1 As shown, the multi-stage ultra-low temperature dehumidification circulation treatment system includes a dryer 1, an air-to-air heat exchanger 2, a low-temperature evaporation module, at least one ultra-low temperature evaporation module, a low-temperature heat exchange module, at least one ultra-low temperature heat exchange module, an electric auxiliary heater 16 and a circulating fan 17. The low-temperature evaporation module includes at least two low-temperature evaporators, and at least two low-temperature evaporators are switched by a low-temperature valve group to form an alternating operation. The ultra-low temperature evaporation module includes at least two ultra-low temperature evaporators, and at least two ultra-low temperature evaporators are switched by an ultra-low temperature valve group to form an alternating operation; the low-temperature heat exchange module includes a low-temperature preheater 13 and a low-temperature heater 14, and the ultra-low temperature heat exchange module includes an ultra-low temperature preheater 12 and an ultra-low temperature heater 15; the dryer 1, the air-to-air heat exchanger 2, the low-temperature evaporation module, the ultra-low temperature evaporation module, the ultra-low temperature preheater 12, the low-temperature preheater 13, the air-to-air heat exchanger 2, the low-temperature heater 14, the ultra-low temperature heater 15, the electric auxiliary heater 16, the circulating fan 17 and the dryer 1 are connected in sequence to form a drying circulation loop.

[0043] The dryer 1 may be a drying terminal formed by different equipment such as a fluidized bed, an air inlet is arranged on one side of the dryer 1, and an air outlet is arranged on the top of the dryer 1. The air-to-air heat exchanger 2 has a hot air inlet and a hot air outlet that are connected, the air-to-air heat exchanger 2 also has a cold air inlet and a cold air outlet that are connected, and a heat exchange drain port 3 is also arranged on the air-to-air heat exchanger 2.

[0044] The circulating fan 17 is specifically a variable frequency fan. The degree of frost in the evaporator will affect the system pressure drop. The use of a variable frequency fan can better cope with the pressure changes inside the system.

[0045] The low temperature evaporation module may also use only one low temperature evaporator, so that one low temperature evaporator works continuously, and the function of switching and alternating operation cannot be performed. The ultra-low temperature evaporation module may also use only one ultra-low temperature evaporator, so that one ultra-low temperature evaporator works continuously, and the function of switching and alternating operation cannot be performed.

[0046] The dehumidification cycle treatment system consists of three parts: air circulation system; low temperature refrigeration system; ultra-low temperature refrigeration system. The air circulation system is a closed circulation system, and each component is connected by air ducts. The low temperature refrigeration system and ultra-low temperature refrigeration system are connected by pipelines, forming two independent refrigeration circulation systems.

[0047] In order to ensure the operation effect, reduce the heat exchange between the air circulation system and the outside world, and prevent condensation in the system, the air circulation system and the dryer 1 are insulated.

[0048] Preferably, the low-temperature heat exchange module further includes a low-temperature return air solenoid valve, a low-temperature compressor 18, a low-temperature condenser 19, a low-temperature liquid storage device 20, a low-temperature liquid supply solenoid valve and a low-temperature expansion valve, and the low-temperature evaporator, the low-temperature return air solenoid valve, the low-temperature compressor 18, the low-temperature heater 14, the low-temperature condenser 19, the low-temperature liquid storage device 20, the low-temperature preheater 13, the low-temperature liquid supply solenoid valve, the low-temperature expansion valve and the low-temperature evaporator are connected in sequence to form a low-temperature heat exchange circulation loop;

[0049] This embodiment specifically arranges a low-temperature evaporator 1 4 and a low-temperature evaporator 2 5. The low-temperature evaporator 1 4 is correspondingly connected to a low-temperature return air solenoid valve 1 23, a low-temperature liquid supply solenoid valve 1 21 and a low-temperature expansion valve 1 22; the low-temperature evaporator 2 5 is correspondingly connected to a low-temperature return air solenoid valve 2 26, a low-temperature liquid supply solenoid valve 2 24 and a low-temperature expansion valve 2 25.

[0050] Preferably, the ultra-low temperature heat exchange module also includes an ultra-low temperature return air solenoid valve, an ultra-low temperature compressor 27, an ultra-low temperature condenser 28, an ultra-low temperature liquid reservoir 29, an ultra-low temperature liquid supply solenoid valve and an ultra-low temperature expansion valve, and the ultra-low temperature evaporator, the ultra-low temperature return air solenoid valve, the ultra-low temperature compressor 27, the ultra-low temperature heater 15, the ultra-low temperature condenser 28, the ultra-low temperature liquid reservoir 29, the ultra-low temperature preheater 12, the ultra-low temperature liquid supply solenoid valve, the ultra-low temperature expansion valve and the ultra-low temperature evaporator are connected in sequence to form an ultra-low temperature heat exchange circulation loop.

[0051] In this embodiment, an ultra-low temperature evaporator 1 8 and an ultra-low temperature evaporator 2 9 are specifically arranged. The ultra-low temperature evaporator 1 8 is correspondingly connected to an ultra-low temperature return air solenoid valve 1 32, an ultra-low temperature liquid supply solenoid valve 1 30 and an ultra-low temperature expansion valve 1 31; the ultra-low temperature evaporator 2 9 is correspondingly connected to an ultra-low temperature return air solenoid valve 2 35, an ultra-low temperature liquid supply solenoid valve 2 33 and an ultra-low temperature expansion valve 2 34.

[0052] Preferably, the low-temperature valve group includes a low-temperature air inlet valve connected to the inlet of the low-temperature evaporator, and a low-temperature air outlet valve connected to the outlet of the low-temperature evaporator, and a low-temperature drain port is provided at the bottom of the low-temperature evaporator;

[0053] In this embodiment, low-temperature evaporator 1 4 and low-temperature evaporator 2 5 are specifically provided. Low-temperature evaporator 1 4 is correspondingly connected to low-temperature air inlet valve 1 36, low-temperature air outlet valve 1 38 and low-temperature drain port 1 6; low-temperature air inlet valve 1 36 and low-temperature air outlet valve 1 38 are opened to enable low-temperature evaporator 1 4, while low-temperature air inlet valve 2 37 and low-temperature air outlet valve 2 39 are in a closed state. Low-temperature evaporator 2 5 is correspondingly connected to low-temperature air inlet valve 2 37, low-temperature air outlet valve 2 39 and low-temperature drain port 2 7; low-temperature air inlet valve 2 37 and low-temperature air outlet valve 2 39 are opened to enable low-temperature evaporator 2 5, while low-temperature air inlet valve 1 36 and low-temperature air outlet valve 1 38 are in a closed state.

[0054] Preferably, the ultra-low temperature valve group includes an ultra-low temperature air inlet valve connected to the inlet of the ultra-low temperature evaporator, and an ultra-low temperature air outlet valve connected to the outlet of the ultra-low temperature evaporator, and an ultra-low temperature drain outlet is arranged at the bottom of the ultra-low temperature evaporator.

[0055] In this embodiment, ultra-low temperature evaporator 18 and ultra-low temperature evaporator 29 are specifically provided. Ultra-low temperature evaporator 18 is correspondingly connected to ultra-low temperature air inlet valve 140, ultra-low temperature air outlet valve 142 and ultra-low temperature drain port 10; ultra-low temperature air inlet valve 140 and ultra-low temperature air outlet valve 142 are opened to enable ultra-low temperature evaporator 18, while ultra-low temperature air inlet valve 241 and ultra-low temperature air outlet valve 243 are in a closed state. Ultra-low temperature evaporator 29 is correspondingly connected to ultra-low temperature air inlet valve 241, ultra-low temperature air outlet valve 243 and ultra-low temperature drain port 211; ultra-low temperature air inlet valve 241 and ultra-low temperature air outlet valve 243 are opened to enable ultra-low temperature evaporator 29, while ultra-low temperature air inlet valve 140 and ultra-low temperature air outlet valve 142 are in a closed state.

[0056] like Figure 1 As shown, an operation method of a multi-stage ultra-low temperature dehumidification cycle treatment system comprises the following steps:

[0057] S1, placing the workpiece in the dryer 1, starting the circulating fan 17 to blow high-temperature dry hot air into the dryer 1 to dehumidify the workpiece; during the drying process, the high-humidity air flows out of the dryer 1 and enters the air-to-air heat exchanger 2. After completing the sensible heat exchange, the moisture content of the high-humidity air is reduced by one level, and the temperature is reduced by one level to form a first-level cooling airflow, and the condensed water is discharged from the air-to-air heat exchanger 2;

[0058] S2, the first-level cooling airflow flows out of the air-to-air heat exchanger 2 and enters one of the low-temperature evaporators of the low-temperature evaporation module. After the currently working low-temperature evaporator is frosted, the low-temperature valve group switches to other low-temperature evaporators. The frosted low-temperature evaporator can be defrosted by electric defrosting, external air defrosting, hot air defrosting, etc. The low-temperature evaporator that has completed defrosting is used as a standby evaporator. The two evaporators are switched in rotation to achieve the continuity of the cooling process; after the first-level cooling airflow undergoes heat and moisture exchange, the moisture content is reduced by one level and the temperature is reduced by one level to form a second-level cooling airflow, and the condensed water is discharged from the low-temperature evaporator;

[0059] The air temperature range in the low-temperature evaporator is controlled at -5℃~-20℃, and the corresponding evaporation temperature range is -10℃~-25℃; the moisture content range of the secondary cooling airflow is 2.3~0.6g / kg; specifically, when the air is treated to -5℃, the moisture content is 2.3g / kg; when the air is treated to -20℃, the moisture content is 0.6g / kg.

[0060] Preferably, after one of the low-temperature evaporators in the low-temperature evaporation module has been running for a cumulative total of 4 to 6 hours, the low-temperature evaporator enters the defrost process and switches to another low-temperature evaporator to start operation; the cumulative running time is adjustable and can be adjusted continuously during the test phase to find the best defrost time. At least one defrost temperature sensor is arranged in the low-temperature evaporator, and the defrost temperature sensor is close to the coil of the low-temperature evaporator. There can be one defrost temperature sensor or multiple defrost temperature sensors that are evenly arranged, and the average value of the defrost temperatures is taken by the multiple defrost temperature sensors. When the defrost temperature of the low-temperature evaporator is lower than the defrost switching temperature, the low-temperature evaporator enters the defrost process and switches to another low-temperature evaporator to start operation; the defrost switching temperature is the low-temperature evaporator refrigeration shutdown temperature minus 8 to 15°C. This defrost switching temperature is adjustable and can be adjusted continuously during the test phase to find the best defrost switching temperature;

[0061] S3, the secondary cooling airflow flows out of the low-temperature evaporation module and enters one of the ultra-low temperature evaporators of the ultra-low temperature evaporation module. After the ultra-low temperature evaporator currently working is frosted, the ultra-low temperature valve group switches to other ultra-low temperature evaporators. The frosted ultra-low temperature evaporator can be defrosted by electric defrosting, external air defrosting, hot air defrosting, etc. The ultra-low temperature evaporator that has completed defrosting is used as a standby evaporator. The two evaporators are switched in rotation to achieve the continuity of the cooling process; after the secondary cooling airflow undergoes heat and moisture exchange, the moisture content is reduced by one level and the temperature is reduced by one level to form a third-level cooling airflow, and the condensed water is discharged from the ultra-low temperature evaporator;

[0062] The air temperature range in the ultra-low temperature evaporator is controlled at -40℃~-60℃, and the corresponding evaporation temperature range is -45℃~-65℃; the moisture content of the three-stage cooling airflow reaches below 0.1g / kg, and the relative humidity is 95%.

[0063] Preferably, after one of the ultra-low temperature evaporators in the ultra-low temperature evaporation module has been running for a total of 8 to 10 hours, the ultra-low temperature evaporator enters the defrost process and switches to another ultra-low temperature evaporator to start running; the cumulative running time is adjustable and can be adjusted continuously during the test phase to find the best defrost time. At least one defrost temperature sensor is arranged in the ultra-low temperature evaporator, and the defrost temperature sensor is close to the coil of the ultra-low temperature evaporator. The defrost temperature sensor can be one or multiple defrost temperature sensors arranged evenly, and the average value of the defrost temperatures is taken by multiple defrost temperature sensors. When the defrost temperature of the ultra-low temperature evaporator is lower than the defrost switching temperature, the ultra-low temperature evaporator enters the defrost process and switches to another ultra-low temperature evaporator to start running; the defrost switching temperature is the ultra-low temperature evaporator refrigeration shutdown temperature minus 8 to 15°C. This defrost switching temperature is adjustable and can be adjusted continuously during the test phase to find the best defrost switching temperature.

[0064] S4, the three-stage cooling airflow flows out of the ultra-low temperature evaporation module and enters the ultra-low temperature preheater 12, the three-stage cooling airflow passes through the ultra-low temperature preheater 12 to absorb heat, the temperature is increased by one level, the moisture content remains unchanged, and the relative humidity is reduced by one level, forming a first-stage warming airflow; the first-stage warming airflow flows out of the ultra-low temperature preheater 12 and enters the low temperature preheater 13, the first-stage warming airflow passes through the low temperature preheater 13 to absorb heat, the temperature is increased by one level, the moisture content remains unchanged, and the relative humidity is reduced by one level, forming a second-stage warming airflow;

[0065] S5, the secondary heated air flows out of the low-temperature preheater 13 and enters the air-to-air heat exchanger 2, and the secondary heated air exchanges heat and moisture with the high-humidity air, the temperature is increased by one level, the moisture content remains unchanged, and the relative humidity is reduced by one level, forming a tertiary heated air flow;

[0066] The temperature of the secondary heated airflow entering the gas-to-gas heat exchanger 2 is above 0°C. By controlling the heat exchange capacity of the ultra-low temperature preheater 12 and the low temperature preheater 13, the temperature of the secondary heated airflow at the outlet of the low temperature preheater 13 is controlled at about 0°C to prevent frost in the gas-to-gas heat exchanger 2.

[0067] S6, the three-stage warming airflow flows out of the air-to-air heat exchanger 2 and enters the low-temperature heater 14, the three-stage warming airflow exchanges heat with the high-temperature exhaust gas, the temperature increases by one level, the moisture content remains unchanged, and the relative humidity decreases by one level, forming a four-stage warming airflow; the four-stage warming airflow flows out of the low-temperature heater 14 and enters the ultra-low-temperature heater 15, the four-stage warming airflow exchanges heat with the high-temperature exhaust gas, the temperature increases by one level, the moisture content remains unchanged, and the relative humidity decreases by one level, forming a five-stage warming airflow;

[0068] S7, the five-stage heated air flows out of the ultra-low temperature heater 15 and enters the electric auxiliary heater 16. The five-stage heated air is electrically heated, the temperature is increased by one level, the moisture content remains unchanged, and the relative humidity is reduced by one level, forming a six-stage heated air flow; according to the temperature requirements of the material, the heating outlet temperature is ensured and kept constant by controlling the electric auxiliary heater 16. The six-stage heated air flow is pressurized by the circulating fan 17 and enters the dryer 1 again for dehumidification.

[0069] When the temperature of the electric auxiliary heater 16 is controlled at 40°C, the relative humidity of the outlet air of the electric auxiliary heater 16 is not higher than 0.2%; the moisture content of the six-stage heated airflow reaches below 0.1g / kg, and the relative humidity is 0.2%. After six-stage heating, the final airflow reaches a high-temperature dry state and becomes an ideal desiccant.

[0070] Preferably, the low-temperature and low-pressure gaseous refrigerant flows out of the low-temperature evaporator and enters the low-temperature compressor 18 through the low-temperature return gas solenoid valve. The low-temperature compressor 18 discharges the high-temperature and high-pressure gaseous refrigerant and enters the low-temperature heater 14 to complete heat exchange. The temperature of the gaseous refrigerant is reduced and enters the low-temperature condenser 19 for condensation. The condensed high-temperature liquid refrigerant enters the low-temperature liquid storage tank 20 and then enters the low-temperature preheater 13 for heat exchange. The temperature of the liquid refrigerant is reduced to complete supercooling. The supercooled liquid refrigerant passes through the low-temperature liquid supply solenoid valve and enters the low-temperature expansion valve for throttling. The throttled low-temperature and low-pressure liquid refrigerant enters the low-temperature evaporator to absorb heat and evaporate to become a low-temperature and low-pressure gaseous refrigerant.

[0071] At least one low-temperature temperature sensor is set in the low-temperature evaporator. Specifically, a low-temperature temperature sensor can be set at the outlet of the low-temperature evaporator, or low-temperature temperature sensors can be set at multiple different positions inside the low-temperature evaporator, and then the average value of multiple temperature values ​​is obtained. The air temperature range in the low-temperature evaporator is -5 to -20℃; multiple working conditions can be set within the range of -5 to -20℃ for low-temperature air treatment. For example, if the design treatment is -15℃, the general start-stop temperature is ±2 or ±3℃, that is, -13 start, -17 stop or -12 start, -18 stop.

[0072] Preferably, the low-temperature and low-pressure gaseous refrigerant flows out of the ultra-low-temperature evaporator and enters the ultra-low-temperature compressor 27 through the ultra-low-temperature return air solenoid valve. The ultra-low-temperature compressor 27 discharges the high-temperature and high-pressure gaseous refrigerant and enters the ultra-low-temperature heater 15 to complete heat exchange. The temperature of the gaseous refrigerant is reduced and enters the ultra-low-temperature condenser 28 for condensation. The condensed high-temperature liquid refrigerant enters the ultra-low-temperature liquid storage tank 29 and then enters the ultra-low-temperature preheater 12 for heat exchange. The temperature of the liquid refrigerant is reduced to complete supercooling. The supercooled liquid refrigerant passes through the ultra-low-temperature liquid supply solenoid valve and enters the ultra-low-temperature expansion valve for throttling. The low-temperature and low-pressure liquid refrigerant after throttling enters the ultra-low-temperature evaporator to absorb heat and evaporate into a low-temperature and low-pressure gaseous refrigerant.

[0073] At least one ultra-low temperature sensor is set in the ultra-low temperature evaporator. Specifically, an ultra-low temperature sensor can be set at the outlet of the ultra-low temperature evaporator, or ultra-low temperature sensors can be set at multiple different positions inside the ultra-low temperature evaporator, and then the average value of multiple temperature values ​​is obtained. The air temperature range in the ultra-low temperature evaporator is -40 to -60°C. Various working conditions can be set within the range of -40 to -60°C for ultra-low temperature air treatment.

[0074] The specific embodiments described herein are merely examples of the spirit of the present invention. A person skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described or replace them in a similar manner, but will not deviate from the spirit of the present invention or exceed the defined scope. Although the present invention is described and described in detail in the drawings and the foregoing description, such descriptions and descriptions are considered to be illustrative or exemplary rather than restrictive. It should be understood that within the scope of the following claims, changes and modifications may be made by a person of ordinary skill. Specifically, the present invention encompasses additional embodiments having any combination of features from the above-mentioned different embodiments. With respect to the use of the expression "generally" or "substantially", this patent application should be understood to disclose that these features and values ​​are also fully satisfied, i.e., there is no aforementioned characterization as "generally" or "substantially".

[0075] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A multi-stage ultra-low temperature dehumidification circulation treatment system, comprising a dryer, an air-to-air heat exchanger, a low-temperature evaporation module, at least one ultra-low temperature evaporation module, a low-temperature heat exchange module, at least one ultra-low temperature heat exchange module, an electric auxiliary heater and a circulation fan, characterized in that: The low-temperature evaporation module includes at least two low-temperature evaporators, and at least two low-temperature evaporators are switched by a low-temperature valve group to form alternating operation. The ultra-low-temperature evaporation module includes at least two ultra-low-temperature evaporators, and at least two ultra-low-temperature evaporators are switched by an ultra-low-temperature valve group to form alternating operation; the low-temperature heat exchange module includes a low-temperature preheater and a low-temperature heater, and the ultra-low-temperature heat exchange module includes an ultra-low-temperature preheater and an ultra-low-temperature heater; the dryer, the gas-to-gas heat exchanger, the low-temperature evaporation module, the ultra-low-temperature evaporation module, the ultra-low-temperature preheater, the low-temperature preheater, the gas-to-gas heat exchanger, the low-temperature heater, the ultra-low-temperature heater, the electric auxiliary heater, the circulating fan and the dryer are connected in sequence to form a drying circulation loop.

2. The multi-stage ultra-low temperature dehumidification cycle treatment system according to claim 1, characterized in that: The low-temperature heat exchange module also includes a low-temperature return air solenoid valve, a low-temperature compressor, a low-temperature condenser, a low-temperature liquid reservoir, a low-temperature liquid supply solenoid valve and a low-temperature expansion valve, and the low-temperature evaporator, the low-temperature return air solenoid valve, the low-temperature compressor, the low-temperature heater, the low-temperature condenser, the low-temperature liquid reservoir, the low-temperature preheater, the low-temperature liquid supply solenoid valve, the low-temperature expansion valve and the low-temperature evaporator are connected in order to form a low-temperature heat exchange circulation loop; The ultra-low temperature heat exchange module also includes an ultra-low temperature return air solenoid valve, an ultra-low temperature compressor, an ultra-low temperature condenser, an ultra-low temperature liquid reservoir, an ultra-low temperature liquid supply solenoid valve and an ultra-low temperature expansion valve. The ultra-low temperature evaporator, the ultra-low temperature return air solenoid valve, the ultra-low temperature compressor, the ultra-low temperature heater, the ultra-low temperature condenser, the ultra-low temperature liquid reservoir, the ultra-low temperature preheater, the ultra-low temperature liquid supply solenoid valve, the ultra-low temperature expansion valve and the ultra-low temperature evaporator are connected in sequence to form an ultra-low temperature heat exchange circulation loop.

3. The multi-stage ultra-low temperature dehumidification cycle treatment system according to claim 1, characterized in that: The low-temperature valve group includes a low-temperature air inlet valve connected to the inlet of the low-temperature evaporator, and a low-temperature air outlet valve connected to the outlet of the low-temperature evaporator, and a low-temperature drain port is arranged at the bottom of the low-temperature evaporator; The ultra-low temperature valve group includes an ultra-low temperature air inlet valve connected to the inlet of the ultra-low temperature evaporator, and an ultra-low temperature air outlet valve connected to the outlet of the ultra-low temperature evaporator. An ultra-low temperature drain port is arranged at the bottom of the ultra-low temperature evaporator.

4. A method for operating a multi-stage ultra-low temperature dehumidification cycle treatment system, characterized in that: The following steps are involved: S1. Place the workpiece in the dryer, start the circulating fan to blow high-temperature dry hot air into the dryer to dehumidify the workpiece; during the drying process, the high-humidity air flows out of the dryer and enters the air-to-air heat exchanger. After the sensible heat exchange is completed, the moisture content and temperature of the high-humidity air are reduced by one level to form a first-level cooling airflow, and the condensed water is discharged from the air-to-air heat exchanger; S2, the first-stage cooling airflow flows out of the air-to-air heat exchanger and enters one of the low-temperature evaporators of the low-temperature evaporation module. After the currently working low-temperature evaporator is frosted, the low-temperature valve group switches to other low-temperature evaporators, and the frosted low-temperature evaporator is defrosted; after the first-stage cooling airflow undergoes heat and moisture exchange, the moisture content is reduced by one level, and the temperature is reduced by one level to form a second-stage cooling airflow, and the condensed water is discharged from the low-temperature evaporator; S3, the secondary cooling airflow flows out of the low-temperature evaporation module and enters one of the ultra-low temperature evaporators of the ultra-low temperature evaporation module. After the ultra-low temperature evaporator currently working is frosted, the ultra-low temperature valve group switches to other ultra-low temperature evaporators, and the frosted ultra-low temperature evaporator is defrosted; after the secondary cooling airflow undergoes heat and moisture exchange, the moisture content is reduced by one level, and the temperature is reduced by one level to form a third-level cooling airflow, and the condensed water is discharged from the ultra-low temperature evaporator; S4, the three-stage cooling airflow flows out of the ultra-low temperature evaporation module and enters the ultra-low temperature preheater. The three-stage cooling airflow absorbs heat through the ultra-low temperature preheater, the temperature rises by one level, the moisture content remains unchanged, and the relative humidity decreases by one level, forming a first-stage warming airflow; The first-stage warming airflow flows out of the ultra-low temperature preheater and enters the low temperature preheater. The first-stage warming airflow absorbs heat through the low temperature preheater, and the temperature is increased by one level, the moisture content remains unchanged, and the relative humidity is reduced by one level, forming a second-stage warming airflow; S5, the secondary warming airflow flows out of the low-temperature preheater and enters the air-to-air heat exchanger, and the secondary warming airflow exchanges heat and moisture with the high-humidity air, the temperature rises by one level, the moisture content remains unchanged, and the relative humidity decreases by one level, forming a tertiary warming airflow; S6, the three-stage warming airflow flows out of the air-to-air heat exchanger and enters the low-temperature heater, the three-stage warming airflow exchanges heat with the high-temperature exhaust gas, the temperature increases by one level, the moisture content remains unchanged, and the relative humidity decreases by one level, forming a four-stage warming airflow; the four-stage warming airflow flows out of the low-temperature heater and enters the ultra-low-temperature heater, the four-stage warming airflow exchanges heat with the high-temperature exhaust gas, the temperature increases by one level, the moisture content remains unchanged, and the relative humidity decreases by one level, forming a five-stage warming airflow; S7, the five-stage heated airflow flows out of the ultra-low temperature heater and enters the electric auxiliary heater. The five-stage heated airflow is electrically heated, the temperature is increased by one level, the moisture content remains unchanged, and the relative humidity is reduced by one level, forming a six-stage heated airflow; the six-stage heated airflow is pressurized by the circulating fan and enters the dryer again for dehumidification.

5. The operating method of the multi-stage ultra-low temperature dehumidification cycle treatment system according to claim 4, characterized in that: In step S2, the air temperature in the low-temperature evaporator is controlled within a range of -5°C to -20°C, and the corresponding evaporation temperature range is -10°C to -25°C; the moisture content of the secondary cooling airflow ranges from 2.3 to 0.6 g / kg; In step S3, the air temperature range in the ultra-low temperature evaporator is controlled at -40°C to -60°C, and the corresponding evaporation temperature range is -45°C to -65°C; the moisture content of the three-stage cooling airflow reaches below 0.1g / kg, and the relative humidity is 95%.

6. The method for operating the multi-stage ultra-low temperature dehumidification cycle treatment system according to claim 4, characterized in that: In step S5, the temperature of the secondary heated airflow entering the gas-to-gas heat exchanger is above 0°C.

7. The operating method of the multi-stage ultra-low temperature dehumidification cycle treatment system according to claim 4, characterized in that: In step S7, when the temperature of the electric auxiliary heater is controlled to be 40°C, the relative humidity of the outlet air of the electric auxiliary heater is not higher than 0.2%; the moisture content of the six-stage heated air flow reaches below 0.1g / kg, and the relative humidity is 0.2%.

8. The method for operating the multi-stage ultra-low temperature dehumidification cycle treatment system according to claim 5, characterized in that: The low-temperature and low-pressure gaseous refrigerant flows out of the low-temperature evaporator and enters the low-temperature compressor through the low-temperature return gas solenoid valve. The low-temperature compressor discharges the high-temperature and high-pressure gaseous refrigerant and enters the low-temperature heater to complete heat exchange. The temperature of the gaseous refrigerant is reduced and enters the low-temperature condenser for condensation. The condensed high-temperature liquid refrigerant enters the low-temperature liquid storage device and then enters the low-temperature preheater for heat exchange. The temperature of the liquid refrigerant is reduced to complete supercooling. The supercooled liquid refrigerant passes through the low-temperature liquid supply solenoid valve and enters the low-temperature expansion valve for throttling. The throttled low-temperature and low-pressure liquid refrigerant enters the low-temperature evaporator to absorb heat and evaporate into a low-temperature and low-pressure gaseous refrigerant. The low-temperature and low-pressure gaseous refrigerant flows out of the ultra-low-temperature evaporator and enters the ultra-low-temperature compressor through the ultra-low-temperature return gas solenoid valve. The ultra-low-temperature compressor discharges the high-temperature and high-pressure gaseous refrigerant and enters the ultra-low-temperature heater to complete the heat exchange. The temperature of the gaseous refrigerant is reduced and enters the ultra-low-temperature condenser for condensation. The condensed high-temperature liquid refrigerant enters the ultra-low-temperature liquid storage device and then enters the ultra-low-temperature preheater for heat exchange. The temperature of the liquid refrigerant is reduced to complete supercooling. The supercooled liquid refrigerant passes through the ultra-low-temperature liquid supply solenoid valve and enters the ultra-low-temperature expansion valve for throttling. The low-temperature and low-pressure liquid refrigerant after throttling enters the ultra-low-temperature evaporator to absorb heat and evaporate into a low-temperature and low-pressure gaseous refrigerant.

9. The operating method of the multi-stage ultra-low temperature dehumidification cycle treatment system according to claim 8, characterized in that: At least one low-temperature temperature sensor is arranged in the low-temperature evaporator, and the air temperature range in the low-temperature evaporator is -5 to -20°C; At least one ultra-low temperature sensor is arranged in the ultra-low temperature evaporator, and the air temperature range in the ultra-low temperature evaporator is -40 to -60°C.

10. The operating method of the multi-stage ultra-low temperature dehumidification cycle treatment system according to claim 4, characterized in that: After one of the low-temperature evaporators in the low-temperature evaporation module has been running for 4 to 6 hours, the low-temperature evaporator enters the defrosting process and switches to another low-temperature evaporator to start running; at least one defrosting temperature sensor is set in the low-temperature evaporator. When the defrosting temperature of the low-temperature evaporator is lower than the defrosting switching temperature, the low-temperature evaporator enters the defrosting process and switches to another low-temperature evaporator to start running; the defrosting switching temperature is the low-temperature evaporator refrigeration shutdown temperature minus 8 to 15°C; After one of the ultra-low temperature evaporators in the ultra-low temperature evaporation module has run for a total of 8 to 10 hours, the ultra-low temperature evaporator enters the defrost process and switches to another ultra-low temperature evaporator to start operation; at least one defrost temperature sensor is arranged in the ultra-low temperature evaporator, and when the defrost temperature of the ultra-low temperature evaporator is lower than the defrost switching temperature, the ultra-low temperature evaporator enters the defrost process and switches to another ultra-low temperature evaporator to start operation; the defrost switching temperature is the ultra-low temperature evaporator refrigeration shutdown temperature minus 8 to 15°C.

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