Freeze dryer carbon dioxide refrigeration and heating and negative pressure defrosting water recovery process method

Abstract

The invention relates to a carbon dioxide refrigeration and heating and negative pressure defrosting water recovery process method for a freeze dryer. According to the process method, a gas cooler, a heating plate group, a heating medium pump and the like of a carbon dioxide heating part are included; the carbon dioxide refrigeration part comprises a low circulation barrel, a refrigerant pump, a cold trap, an air cooler and the like; supercooling the common part and the like; and the negative-pressure defrosting water recovery part comprises a negative-pressure steam generator, a drainage pump, a recovery water tank and the like. The method is characterized in that an environment-friendly working medium is selected, a carbon dioxide transcritical cycle technology is adopted, the excellent low-temperature refrigeration performance and the transcritical temperature slippage heat exchange characteristic of carbon dioxide are fully utilized, the effect that the COP of both refrigeration and heating of a reverse Carnot cycle is larger than 1 is exerted, the freeze-drying refrigeration and heating processes are combined into one, heating equipment with the COP smaller than 1 and power consumption are omitted, and the cost is reduced. Therefore, the super effect that the comprehensive COP is greater than 6 is achieved; the negative pressure defrosting technology is adopted, a low-quality heat source of the system is fully utilized, complete recovery of pure plant raw material water is achieved, and the raw material utilization rate is close to 100%.

Description

Technical Field

[0001] This invention relates to a complete system for energy-saving and environmentally friendly utilization of freeze dryers, and specifically to a process method for carbon dioxide refrigeration and heating and negative pressure defrosting water recovery in freeze dryers. Background Technology

[0002] With social development, progress of the times, and improvement of people's living standards, the food industry is moving towards a direction of nutrition, health, convenience, speed, and environmental friendliness. In recent years, freeze-drying technology for pure natural, high-quality, easy-to-store and transport, and ecologically healthy foods has gained popularity and attracted widespread attention in the food industry. However, its fatal weaknesses—high energy consumption (3-5 times that of drying), low yield (more than 80% moisture loss in fruits and vegetables), and lack of environmental friendliness (refrigeration refrigerant CWP > 1000, emissions from heating and defrosting)—have greatly hindered the widespread application of this high-end drying technology. Especially under the new dual-circulation development pattern of "rural revitalization, green development, carbon emission reduction, and industrial upgrading," energy saving, environmental protection, and improved raw material utilization of traditional freeze dryers have become urgent priorities. This invention uses the green and environmentally friendly working fluid CO2 and innovative CO2 transcritical refrigeration and heating parallel technology, which combines the freeze-drying refrigeration and heating processes into one, eliminating the heating equipment and power consumption of COP<1, and thus producing a super efficiency with a comprehensive COP>6; it adopts negative pressure defrosting water recycling and comprehensive utilization technology, so that the utilization rate of raw materials is close to 100%, which can be described as a revolutionary improvement in the energy-saving, environmental protection and comprehensive utilization of freeze dryers.

[0003] Freeze-drying technology involves rapidly freezing water-containing materials and then heating them in a vacuum environment to directly sublimate the ice crystals within the material, thus obtaining a dried product. During freeze-drying, the material must undergo two extremely energy-intensive processes: deep freezing and sublimation. Therefore, the high energy consumption per unit of dehydration in traditional freeze-drying equipment is a key reason why freeze-drying technology is difficult to widely adopt. Furthermore, the loss of over 80% of the moisture content in fruits and vegetables after freeze-drying is also unacceptable to most food manufacturers. Therefore, based on in-depth analysis and calculation of the freeze-drying process and supporting equipment, and theoretical and practical considerations, a "process method for transcritical carbon dioxide refrigeration and heating and negative pressure defrosting water recovery in a freeze dryer" was designed. This method fully utilizes the excellent low-temperature refrigeration performance and transcritical temperature glide heat transfer characteristics of carbon dioxide, leverages the effect of reverse Carnot cycle refrigeration and heating with a COP > 1, and combines the freeze-drying refrigeration and heating processes into one, enabling the freeze dryer's cooling equipment to perform dual-effect cooling and heating functions. By utilizing the existing vacuum unit of the freeze dryer, the negative pressure steam generator can fully utilize the low-quality heat source in the medium-temperature section of the working fluid gas cooler under relatively low temperature conditions, achieving a fully self-melting process of ice and water without additional energy, further improving the comprehensive utilization rate of resources and the purity of the melted plant water, and striving to create the best economic and social benefits. Summary of the Invention

[0004] The purpose of this invention is to solve the thorny problems of high energy consumption, low output, and environmental unfriendliness in traditional freeze-drying processes. It provides a complete system and process for carbon dioxide refrigeration and heating, negative pressure defrosting, and water recovery in a freeze dryer. It uses an environmentally friendly refrigeration and vacuum equipment to simultaneously complete the comprehensive utilization process of quick freezing, refrigeration, heating, negative pressure defrosting, and pure plant water recovery in a freeze dryer.

[0005] The technical solution adopted by the present invention to solve the problem is: a process method for carbon dioxide refrigeration and heating and negative pressure defrosting water recovery in a freeze dryer, including a carbon dioxide heating part A; a common part B; a carbon dioxide refrigeration part C; and a negative pressure defrosting water recovery part D.

[0006] The carbon dioxide heating section A comprises a gas cooler; a medium-temperature section inlet; a medium-temperature section outlet; a medium-temperature working gas outlet; a high-temperature working gas inlet; a high-temperature section inlet; a high-temperature section outlet; a high-pressure stage exhaust port of the transcritical carbon dioxide chiller; a generator heating water supply port; a generator heating return water port; a heating plate assembly; heating plate assembly inlet 1 and inlet 2; heating plate assembly outlet 1 and outlet 2; a heating plate assembly inlet electric regulating valve; a heating plate assembly heat pump; a heating plate assembly electric valve; a heating plate assembly water supply tee; a heating plate assembly water supply electric valve; a heat recovery system water supply port; a heating plate assembly outlet electric valve; a heating plate assembly return water tee; a heating plate assembly return water electric valve; and a heat recovery system return water port. The high-pressure stage exhaust port of the transcritical carbon dioxide chiller is connected to the high-temperature working gas inlet of the gas cooler, and is connected to the medium-temperature working gas outlet through the high-temperature and medium-temperature section heat dissipation pipes of the gas cooler. The gas cooler's high-temperature section outlet is connected to the hot-side inlet of the common section B working fluid subcooler via a pipeline; the heating plate group inlet 1 and heating plate group inlet 2 are connected via a heating plate water supply tee, a heating plate group electric valve, a heating plate group heat medium pump, and a heating plate group inlet electric regulating valve; the other port of the heating plate water supply tee is connected to the heat recovery system water supply port via a heating plate water supply electric valve; the heating plate group outlet 1 and outlet 2 are connected to the gas cooler's high-temperature section inlet via a heating plate group outlet electric valve (1-25) and a heating plate return water tee; the other port of the heating plate return water tee is connected to the heat recovery system return water port via a heating plate return water electric valve; the generator heating return water port at the gas cooler's medium-temperature section inlet and the generator heating water supply port at the gas cooler's medium-temperature section outlet are connected via pipelines, valves, and pumps to the generator heating water outlet's air-cooled medium-temperature return water port and the generator heating water inlet's air-cooled medium-temperature supply water port, respectively.

[0007] The common part B consists of a subcooler; a hot-side inlet; a cold-side outlet; a hot-side outlet; a cold-side inlet; and a low-pressure stage suction port of the transcritical carbon dioxide refrigeration unit. The hot-side inlet, cold-side outlet, hot-side outlet, and cold-side inlet are respectively connected to the medium-temperature working gas outlet of the heating part, the low-pressure stage suction port of the transcritical carbon dioxide refrigeration unit, the electric throttle valve of the refrigeration part, and the electric regulating valve.

[0008] The aforementioned carbon dioxide refrigeration section C comprises a low-temperature circulating tank; a steam inlet; a throttling gas inlet; a steam outlet; two cryogenic liquid outlets; an electric throttling valve; an electric regulating valve; a cold trap; a cold trap inlet; a cold trap outlet; a cold trap electric regulating valve; a cold trap working fluid circulation pump; a cold trap outlet electric valve; a cooler; a cooler inlet; a cooler outlet; a cooler electric regulating valve; a cooler working fluid circulation pump; and a cooler outlet electric valve. The throttling gas inlet and steam outlet of the low-temperature circulating tank are respectively connected to the electric throttling valve and the electric regulating valve. The cryogenic liquid outlet of the low-temperature circulating tank is connected to the cold trap inlet via the cold trap working fluid circulation pump and the cold trap electric regulating valve. The cold trap outlet is connected to the steam inlet of the low-temperature circulating tank via the cold trap outlet electric valve. The cryogenic liquid outlet of the low-temperature circulating tank is connected to the cooler inlet via the cooler working fluid circulation pump and the cooler electric regulating valve. The cooler outlet is connected to the steam inlet of the low-temperature circulating tank via the cooler outlet electric valve.

[0009] The negative pressure defrost water recovery section D comprises: a negative pressure steam generator; a generator heating water outlet; a heating water outlet electric valve; an air-cooled medium-temperature return water interface; a generator heating water inlet; a heating water inlet electric valve; an air-cooled medium-temperature supply water interface; a generator steam outlet; a generator steam electric valve; a defrost steam inlet; a generator water inlet; a generator water inlet electric valve; a defrost water tee; a defrost drain outlet; a defrost drain electric valve; a defrost drain pump; a recovery water tank; a recovery water tank inlet electric valve; a recovery water tank outlet electric valve; a recovery water purification interface; a negative pressure air extraction port; a negative pressure air extraction electric valve; a vacuum unit interface; a vacuum breaking port; a vacuum breaking electric valve; and a venting interface; a generator heating water outlet; and a generator heating water... The inlet is connected to the return water interface and the feed water interface of the medium-temperature section of the gas cooler via the electric valve for the heating water outlet and the electric regulating valve for the heating water, respectively; the generator steam outlet is connected to the defrost steam inlet of the cold trap via the electric valve for the generator steam; the defrost drain outlet is connected to the generator makeup water inlet via the electric valve for the defrost drain, the defrost drain pump, the defrost water tee, and the electric valve for the generator makeup water; the other interface of the defrost water tee is connected to the recovery water tank via the electric valve for the recovery water inlet; the electric valve for the recovery water tank outlet is connected to the recovery water polishing interface; the negative pressure exhaust port is connected to the vacuum unit interface via the electric valve for the negative pressure exhaust and is connected to the defrost steam inlet via the chamber; the vacuum breaking port of the negative pressure system is connected to the venting interface via the electric valve for the vacuum breaking.

[0010] A process for carbon dioxide refrigeration and heating and negative pressure defrosting water recovery in a freeze dryer comprises the following steps: In this process, the carbon dioxide refrigeration, heating, and negative pressure defrosting water recovery components, along with the freeze dryer control system, are all controlled by a computer + configuration, PLC module + corresponding system measurement and control components, under fully automated program control. This can be controlled locally and remotely via computer or mobile terminal through a 5G network. According to the freeze-drying process requirements, the freeze dryer control system first activates the refrigeration section, first cooling the material for the cold air blower, then cooling the water trap, and simultaneously storing energy for the heat recovery system. When heating is required, the heating section is activated to provide sublimation heat to the heating plate assembly. Finally, the negative pressure defrosting water recovery section is activated to provide defrosting heat to the negative pressure steam generator. After defrosting, the system releases the vacuum, and the defrosting water first replenishes the generator before being recycled to the recovery water tank. Because this complete system adopts a combined cooling and heating parallel scheme, meaning that both the cooling and heating energy in the freeze-drying process are provided by the same transcritical carbon dioxide refrigeration unit, the working sequence of this process is: refrigeration section C; heating section A; negative pressure defrosting water recovery section D.

[0011] C-Refrigeration Section: When air conditioning is required, the air conditioner, air conditioner liquid supply electric regulating valve, air conditioner working fluid circulation pump, and air conditioner outlet electric valve are turned on (at this time, the transcritical carbon dioxide refrigeration unit has already started refrigeration, and the gas cooler stores energy for the heat recovery system). The throttling working fluid liquid below -30°C in the low-temperature circulation tank flows into the air conditioner coil inlet through the low-temperature circulation tank liquid outlet and the air conditioner liquid supply electric regulating valve under the action of the air conditioner working fluid circulation pump. After absorbing heat, the working fluid liquid evaporates into gas and returns to the low-temperature circulation tank through the air conditioner coil outlet and the air conditioner outlet electric valve, completing one air conditioning refrigeration cycle. This cycle continues continuously to complete the process design. After the program is set, operation stops. When cold trap cooling is required, the cold trap liquid supply electric regulating valve, cold trap working fluid circulation pump, and cold trap outlet electric valve are opened (at this time, the carbon dioxide transcritical refrigeration unit has already started cooling, and the gas cooler stores energy for the heat recovery system). The throttling working fluid liquid below -30°C in the low circulation tank flows into the cold trap coil inlet through the low circulation tank liquid outlet and the cold trap liquid supply electric regulating valve under the action of the cold trap working fluid circulation pump. After absorbing the heat of sublimation, the working fluid liquid evaporates into gas and returns to the low circulation tank through the cold trap coil outlet and the cold trap outlet electric valve, completing one cold trap cooling cycle. The cycle continues continuously until the process program is completed and operation stops.

[0012] A-Heating Section: When heating by the heating plate group is required, open the electric regulating valve, heating medium, electric valve, and outlet electric valve of the heating plate group. Simultaneously close the electric valves of the supply and return water interfaces on the two three-way pipe branches leading to the heat recovery system. At this time, the transcritical carbon dioxide refrigeration unit has already started. The high-temperature working fluid gas temperature at the inlet of the high-temperature section heat dissipation coil of the gas cooler can reach over 100℃. Under the action of the heating medium pump of the heating plate group, the cooling water flows into the first and second inlets of the heating plate group through the coolant outlet of the high-temperature section of the gas cooler, the heating plate supply water three-way pipe, the electric valve of the heating plate group, and the electric regulating valve of the heating plate group. The cooling water continuously absorbs heat from the working fluid. The high-temperature working gas is cooled to below 90°C, and the heating plate assembly is heated to above 80°C. The temperature of the heating plate assembly can be adjusted within a certain range according to process requirements. The heated and cooled water flows back to the high-temperature section of the gas cooler through heating plate assembly one, outlet two, the electric valve of the heating plate assembly outlet, and the heating plate return water tee pipe, completing one heating plate assembly heating cycle. This cycle continues continuously until the process program is completed and then the operation stops. At the same time as the heating plate assembly stops heating, the electric valves of the supply and return water on the two supply and return water tee pipe branches are opened to start the freeze dryer heat recovery system. The heat recovery system recovers the heat from the gas cooler and maintains the normal operation of the transcritical carbon dioxide refrigeration unit.

[0013] D-Negative Pressure Defrosting Water Recovery Section: After freeze-drying is completed and the dried product leaves the warehouse, the defrosting system needs to be re-evacuated to the process-set negative pressure value. At this time, the negative pressure suction electric valve and steam electric valve are opened, and the vacuum unit is turned on. Through the vacuum unit interface, along with the defrosting steam inlet and the generator steam outlet, the warehouse and generator are evacuated to a pressure of <6000Pa. After reaching the process-set value, the evacuation electric valve is closed to stop evacuation. The corresponding valves and pumps, such as the negative pressure steam generator heating water electric regulating valve and heating water outlet electric valve, are opened (or closed). The cooling water in the medium-temperature section of the gas cooler is used to power the generator. In the intermediate-temperature section of the gas cooler, the working fluid temperature is above 70°C. Under the action of the generator heating pump, the cooling water flows through the intermediate-temperature section coolant outlet of the gas cooler and the electric regulating valve of the heating water into the inlet of the negative-pressure steam generator coil. While continuously absorbing heat from the working fluid, the cooling water further cools the intermediate-temperature working fluid gas to below 50°C and vaporizes the water in the generator into steam at approximately 6000 Pa. The cooling water, having released its latent heat of vaporization, flows back to the gas cooler through the generator coil outlet and the electric regulating valve of the heating water outlet. In the intermediate temperature section of the cooler, one generator heating cycle is completed, and the cycle continues continuously until the process program is finished and operation stops. Simultaneously with the generator stopping its heating cycle, relevant valves in the heat recovery system are opened, allowing the system to recover the heat from the gas cooling and maintain the normal operation of the transcritical carbon dioxide refrigeration unit. In fact, defrosting begins even as the generator heats up. The negative pressure steam generated by the generator flows continuously into the freeze-drying chamber through the steam outlet, steam electric valve, and defrosting steam inlet. Driven by the energy field, it diffuses onto the ice surface of the cold trap, exchanging heat with the ice. The steam, releasing its latent heat of vaporization, melts the ice into water. This continuous heat exchange continues until the set process time, at which point all the ice has melted, ending the defrosting process. The electric regulating valve for heating water and the electric valve for heating water outlet are then closed, stopping the generator heating system. The electric valve for breaking the vacuum is opened to release the vacuum in the defrosting system. After pressure equalization, the electric valves for defrosting drainage, defrosting drainage pump, and generator water replenishment are opened to replenish water to the generator. Once the set water level is reached, the electric valve for generator water replenishment is closed, and the electric valve for the inlet of the recovery water tank is opened to store all remaining defrosting water in the recovery water tank for use in the defrosting water polishing system. At this point, the defrosting drainage valve pump is shut off, completing the entire negative pressure defrosting water recovery process.

[0014] The beneficial effects of this invention are as follows: This invention, targeting the characteristics of freeze-drying process, fully utilizes the excellent low-temperature refrigeration performance and transcritical temperature glide heat transfer characteristics of carbon dioxide, and leverages the effect of reverse Carnot cycle refrigeration and heating COP>1, combining the freeze-drying refrigeration and heating processes into one, enabling the freeze-drying machine's cooling equipment to perform dual-effect cooling and heating functions; by utilizing the vacuum unit to generate a negative pressure environment, under negative pressure and low temperature conditions, it fully utilizes the low-quality heat source in the medium-temperature section of the working fluid gas cooler to achieve a fully self-melting process of ice and water without additional energy, further improving the comprehensive utilization rate of resources and the purity of the defrosting plant water. Attached Figure Description

[0015] The following is in conjunction with the appendix Figure 1 The following is a detailed explanation using specific examples: Appendix Figure 1 This is a schematic diagram of a freeze dryer's carbon dioxide refrigeration and heating process with negative pressure defrosting and water recovery.

[0016] Figure 1 middle A-Carbon Dioxide Heating Section: 2-10-Gas Cooler; e-1-Medium Temperature Section Inlet; e-2-Medium Temperature Section Outlet; e-3-Medium Temperature Working Gas Outlet; e-4-High Temperature Working Gas Inlet; e-5-High Temperature Section Inlet; e-6-High Temperature Section Outlet; 2-100-High Pressure Stage Exhaust Interface of Carbon Dioxide Transcritical Refrigeration Unit; 10-1'-Generator Heating Return Water Interface; 10-2'-Generator Heating Feed Water Interface; 1-20-Heating Plate Assembly; 20-1-Heating Plate Assembly Outlet 1, 20-2-Heating Plate Assembly Outlet 2; 20-3-Heating plate assembly inlet 1, 20-4-Heating plate assembly inlet 2; 1-21-Heating plate assembly inlet electric regulating valve; 1-22-Heating plate assembly heat medium pump; 1-23-Heating plate assembly electric valve; 1-2a-Heating plate water supply tee; 1-24-Heating plate water supply electric valve; 1-200-Heat recovery system water supply interface; 1-25-Heating plate assembly outlet electric valve; 1-2b-Heating plate return water tee; 1-26-Heating plate return water electric valve; 1-201-Heat recovery system return water interface; B-Common parts: 2-20-Subcooler; f-1-Hot side inlet; f-2-Cold side outlet; f-3-Hot side outlet; f-4-Cold side inlet; 2-200-Low-pressure stage suction port of transcritical CO2 refrigeration unit; C-Carbon Dioxide Refrigeration Section: 2-30-Low Temperature Circulation Tank; g-1-Steam Inlet, g-2-Throttle Gas Inlet; g-3-Steam Outlet; g-4-Cryogenic Liquid Outlet 1, g-5-Cryogenic Liquid Outlet 2; 2-31 Electric Throttling Valve; 2-32 Electric Regulating Valve; 1-30-Cold Trap; 30-2-Cold Trap Inlet; 30-1-Cold Trap Outlet; 1-31-Cold Trap Electric Regulating Valve; 1-32-Cold Trap Working Refrigerant Circulation Pump; 1-33-Cold Trap Outlet Electric Valve; 1-40-Air Cooler; 40-2-Air Cooler Inlet; 40-1-Air Cooler Outlet; 1-41-Air Cooler Electric Regulating Valve; 1-42-Air Cooler Working Refrigerant Circulation Pump; 1-43-Air Cooler Outlet Electric Valve. D-Negative Pressure Defrosting Water Recovery Section: 1-10-Negative Pressure Steam Generator; 10-1-Generator Heating Water Outlet; 1-11-Heating Water Outlet Electric Valve; e-1'-Air-Cooled Medium-Temperature Return Water Interface; 10-2-Generator Heating Water Inlet; 1-15-Heating Water Electric Regulating Valve; e-2'-Air-Cooled Medium-Temperature Feed Water Interface; 10-3-Generator Steam Outlet; 10-5-Generator Steam Electric Valve; d-2-Defrosting Steam Inlet; 10-4-Generator Makeup Inlet; 10-6-Generator Makeup Inlet Water-powered electric valve; d-1b-Defrost water tee; d-1-Defrost drain outlet; d-5-Defrost drain electric valve; d-6-Defrost drain pump; 5-10-Recovery water tank; 5-1-Recovery water tank inlet electric valve; 5-2-Recovery water tank outlet electric valve; 5-100-Recovery water purification interface; d-3-Negative pressure suction port; 3-1-Negative pressure suction electric valve; 3-100-Vacuum unit interface; d-7-Vacuum breaking port; 7-1-Vacuum breaking electric valve; 7-100-Vent interface. Detailed Implementation

[0017] Example, see attached document Figure 1 This includes: A) Carbon dioxide heating section; B) Common section; C) Carbon dioxide refrigeration section; D) Negative pressure defrosting water recovery section.

[0018] The carbon dioxide heating section A comprises a gas cooler 2-10; a medium-temperature section inlet e-1; a medium-temperature section outlet e-2; a medium-temperature working gas outlet e-3; a high-temperature working gas inlet e-4; a high-temperature section inlet e-5; a high-temperature section outlet e-6; a high-pressure stage exhaust port 2-100 for the transcritical carbon dioxide refrigeration unit; a generator heating return water port 10-1'; a generator heating supply water port 10-2'; a heating plate assembly 1-20; heating plate assembly outlet 1 20-1; heating plate assembly outlet 2 20-2; heating plate assembly inlet 1 20-3; heating plate assembly inlet 2 20-4; and a heating plate assembly inlet electric regulating valve 1- 21; Heating plate group heat medium pump 1-22; Heating plate group electric valve 1-23; Heating plate water supply tee 1-2a; Heating plate water supply electric valve 1-24; Heat recovery system water supply interface 1-200; Heating plate group outlet electric valve 1-25; Heating plate return water tee 1-2b; Heating plate return water electric valve 1-26; Heat recovery system return water interface 1-201; The high-pressure stage exhaust interface 2-100 of the carbon dioxide transcritical refrigeration unit is connected to the high-temperature working gas inlet e-4 of the gas cooler 2-10, and is connected to the medium-temperature working gas outlet e-3 through the high-temperature section and medium-temperature section heat dissipation pipes of the gas cooler 2-10, and then through the pipe The water supply is connected to the hot side inlet f-1 of the subcooler 2-20 in the common section B; the outlet e-6 of the high-temperature section of the gas cooler 2-10 is connected to the heating plate group inlet 20-3 and the heating plate group inlet 20-4 through the heating plate group water supply tee 1-2a, the heating plate group electric valve 1-23, the heating plate group heat medium pump 1-22, and the heating plate group inlet electric regulating valve 1-21; the other port of the heating plate group water supply tee 1-2a is connected to the heat recovery system water supply port 1-200 through the heating plate group water supply electric valve 1-24; the heating plate group outlet 20-1 and the heating plate group outlet 20-2 are connected through the heating plate group outlet electric valve (1-2) 5) 1-25. The heating plate return water tee pipe 1-2b is connected to the high temperature section inlet e-5 of the gas cooler 2-10; the other port of the heating plate return water tee pipe 1-2b is connected to the heat recovery system return water port 1-201 through the heating plate return water electric valve 1-26; the generator heating return water port 10-1' of the medium temperature section inlet e-1 of the gas cooler 2-10 and the generator heating water supply port 10-2' of the medium temperature section outlet e-2 are connected to the air-cooled medium temperature return water port e-1' of the generator heating water outlet 10-1 and the air-cooled medium temperature supply water port e-2' of the generator heating water inlet 10-2 through the pipeline valve pump.

[0019] The common part B consists of a subcooler 2-20; a hot-side inlet f-1; a cold-side outlet f-2; a hot-side outlet f-3; a cold-side inlet f-4; and a low-pressure stage suction port 2-200 for the transcritical carbon dioxide refrigeration unit. The hot-side inlet f-1, cold-side outlet f-2, hot-side outlet f-3, and cold-side inlet f-4 are respectively connected to the medium-temperature working gas outlet e-3 of the carbon dioxide heating part (A); the low-pressure stage suction port 2-200 of the transcritical carbon dioxide refrigeration unit; and the electric throttle valve 2-31 and the electric regulating valve 2-32 of the carbon dioxide refrigeration part (C).

[0020] The carbon dioxide refrigeration section C comprises: a low-circulation tank 2-30; a steam inlet g-1, a throttling gas inlet g-2; a steam outlet g-3; a cryogenic liquid outlet one g-4, a cryogenic liquid outlet two g-5; an electric throttling valve 2-31; an electric regulating valve 2-32; a cold trap 1-30; a cold trap inlet 30-2; a cold trap outlet 30-1; a cold trap electric regulating valve 1-31; a cold trap working fluid circulation pump 1-32; a cold trap outlet electric valve 1-33; a cooler 1-40; a cooler inlet 40-2; a cooler outlet 40-1; a cooler electric regulating valve 1-41; a cooler working fluid low-circulation pump 1-42; and a cooler outlet electric valve 1-43. The low-circulation tank 2-30 throttling... Gas inlet g-2 and steam outlet g-3 are connected to electric throttle valve 2-31 and electric regulating valve 2-32, respectively; low-temperature liquid outlet g-4 of low-temperature circulation tank 2-30 is connected to cold trap inlet 30-2 via cold trap working fluid circulation pump 1-32 and cold trap electric regulating valve 1-31; cold trap outlet 30-1 is connected to steam inlet g-1 of low-temperature circulation tank 2-30 via cold trap outlet electric valve 1-33; low-temperature liquid outlet g-5 of low-temperature circulation tank 2-30 is connected to cold air blower inlet 40-2 via cold air blower working fluid low-temperature circulation pump 1-42 and cold air blower electric regulating valve 1-41; cold air blower outlet 40-1 is connected to steam inlet g-1 of low-temperature circulation tank 2-30 via cold air blower outlet electric valve 1-43.

[0021] The negative pressure defrosting water recovery section D comprises: a negative pressure steam generator 1-10; a generator heating water outlet 10-1; a heating water outlet electric valve 1-11; an air-cooled medium-temperature return water interface e-1'; a generator heating water inlet 10-2; a heating water inlet electric valve 1-15; an air-cooled medium-temperature water supply interface e-2'; a generator steam outlet 10-3; a generator steam electric valve 10-5; a defrosting steam inlet d-2; a generator water inlet 10-4; a generator water inlet electric valve 10-6; and a defrosting... Composed of: water tee pipe d-1b; defrost drain outlet d-1; defrost drain electric valve d-5; defrost drain pump d-6; recovery water tank 5-10; recovery water tank inlet electric valve 5-1; recovery water tank outlet electric valve 5-2; recovery water purification interface 5-100; negative pressure suction port d-3; negative pressure suction electric valve 3-1; vacuum unit interface 3-100; vacuum breaking port d-7; vacuum breaking electric valve 7-1; venting interface 7-100; generator heating water outlet 10-1; generator. The heating water inlet 10-2 is connected to the return water interface e-1' and the supply water interface e-2' of the air-cooled medium-temperature section via the heating water outlet electric valve 1-11 and the heating water electric regulating valve 1-15, respectively; the generator steam outlet 10-3 is connected to the cold trap defrost steam inlet d-2 via the generator steam electric valve 10-5; the defrost drain outlet d-1 is connected to the generator via the defrost drain electric valve d-5, the defrost drain pump d-6, the defrost water tee pipe d-1b, and the generator water supply electric valve 10-6. The water inlet 10-4 is connected; the other port of the defrost water tee d-1b is connected to the recovery water tank 5-10 via the recovery water tank inlet electric valve 5-1; the recovery water tank outlet electric valve 5-2 is connected to the recovery water polishing interface 5-100; the negative pressure exhaust port d-3 is connected to the vacuum unit interface 3-100 via the negative pressure exhaust electric valve 3-1, and is connected to the defrost steam inlet d-2 via the chamber; the negative pressure system vacuum breaking port d-7 is connected to the vent interface 7-100 via the vacuum breaking electric valve 7-1.

[0022] A process for carbon dioxide refrigeration and heating and negative pressure defrosting water recovery in a freeze dryer comprises the following steps: In this process, the carbon dioxide refrigeration, heating, and negative pressure defrosting water recovery components, along with the freeze dryer control system, are all controlled by a computer + configuration, PLC module + corresponding system measurement and control components, under fully automatic program control. This can be controlled locally and remotely via computer or mobile terminal through a 5G network. According to the freeze-drying process requirements, the freeze dryer control system first activates the refrigeration section, first cooling the material in the cold air blowers 1-40, then cooling the water traps 1-30, while simultaneously storing energy for the heat recovery system. When heating is required, the heating section is activated to provide sublimation heat to the heating plate group 1-20. Finally, the negative pressure defrosting water recovery section is activated to provide defrosting heat to the negative pressure steam generator 1-10. After defrosting, the system releases the vacuum, and the defrosting water first replenishes the generator before being recovered into the recovery water tank. Since this complete system adopts a parallel cooling and heating scheme, that is, the cooling and heating of the freeze-drying process are both provided by the same transcritical carbon dioxide refrigeration unit, the working sequence of this complete system is: refrigeration section C; heating section A; negative pressure defrosting water recovery section D.

[0023] C-Refrigeration Section: When cooling is required by air cooler 1-40, air cooler 1-40, air cooler electric regulating valve 1-41, air cooler working fluid low-circulation pump 1-42, and air cooler outlet electric valve 1-43 are turned on (at this time, the carbon dioxide transcritical refrigeration unit has already started cooling, and the gas cooler stores energy for the heat recovery system). The throttling working fluid liquid below -30℃ in the low-circulation tank 2-30 flows into air cooler inlet 40-2 through low-temperature liquid outlet 2g-5 and air cooler electric regulating valve 1-41 under the action of air cooler working fluid low-circulation pump 1-42. After absorbing heat, the working fluid liquid evaporates into gas and returns to low-circulation tank 2-30 through air cooler outlet 40-1 and air cooler outlet electric valve 1-43, completing one cooling cycle of air cooler 1-40. This cycle continues continuously to complete the cooling process. After the process setting program is completed, the system stops operating. When cooling is required in cold trap 1-30, the cold trap electric regulating valve 1-31, the cold trap working fluid circulation pump 1-32, and the cold trap outlet electric valve 1-33 are opened (at this time, the carbon dioxide transcritical refrigeration unit has already started cooling, and the gas cooler stores energy for the heat recovery system). The throttling working fluid liquid below -30℃ in the low circulation tank 2-30 flows into the cold trap inlet 30-2 through the low-temperature liquid outlet 1g-4 and the cold trap electric regulating valve 1-31 under the action of the cold trap working fluid circulation pump 1-32. After absorbing the heat of sublimation, the working fluid liquid evaporates into gas and returns to the low circulation tank 2-30 through the cold trap outlet 30-1 and the cold trap outlet electric valve 1-33, completing one cooling cycle of cold trap 1-30. The cycle continues continuously until the process setting program is completed, at which point the system stops operating.

[0024] A-Heating Section: When heating of heating plate group 1-20 is required, open the heating plate group inlet electric regulating valve 1-21, heating plate group heat medium pump 1-22, heating plate group electric valve 1-23, and heating plate group outlet electric valve 1-25. Simultaneously close the heating plate feed water electric valve 1-24 and heating plate return water electric valve 1-26 on the two three-way pipe branches leading to the heat recovery system interface. At this time, the carbon dioxide transcritical refrigeration unit has already started. The high-temperature working gas temperature at the high-temperature working gas inlet e-4 of gas cooler 2-10 can reach over 100℃. Under the action of heating plate group heat medium pump 1-22, cooling water flows into heating plate group inlet 1 20-3 and heating plate group inlet 2 20-4 through the high-temperature section outlet e-6 of gas cooler 2-10, heating plate feed water three-way pipe 1-2a, heating plate group electric valve 1-23, and heating plate group inlet electric regulating valve 1-21. The cooling water continuously... While absorbing the heat of the working fluid, the high-temperature working fluid gas is cooled to below 90°C, and the heating plate assembly is heated to above 80°C. The temperature of the heating plate assembly can be adjusted within a certain range according to process requirements. The heated and cooled water flows back to the high-temperature section of the gas cooler 2-10 through the outlet 20-1 and outlet 20-2 of the heating plate assembly, the outlet electric valve 1-25 of the heating plate assembly, and the return water tee pipe 1-2b of the heating plate assembly, completing one heating cycle of the heating plate assembly 1-20. This cycle continues continuously until the process program is completed and then the operation stops. At the same time as the heating plate assembly 1-20 stops heating, the heating plate water supply electric valve 1-24 and the heating plate water return electric valve 1-26 of the two tee pipe branches leading to the heat recovery system interface are opened, starting the freeze dryer heat recovery system. The heat recovery system recovers the heat from the gas cooler 2-10 and maintains the normal operation of the transcritical carbon dioxide refrigeration unit.

[0025] D-Negative Pressure Defrosting Water Recovery Section: After freeze-drying is completed and the dried product leaves the warehouse, the defrosting system needs to be re-evacuated to the process-set negative pressure value. At this time, open the negative pressure suction electric valve 3-1 and the generator steam electric valve 10-5, and start the vacuum unit. Through the vacuum unit interface 3-100, along with the defrosting steam inlet d-2 and the generator steam outlet 10-3, evacuate the warehouse and generator together to a pressure of <6000Pa. After reaching the process-set value, close the negative pressure suction electric valve 3-1 to stop evacuation. Open (or close) the corresponding valves and pumps such as the heating water electric regulating valve 1-15 and the heating water outlet electric valve 1-11 of the negative pressure steam generator 1-10, and heat the vaporized water in the generator through the medium-temperature section cooling water of the gas cooler 2-10. The transcritical carbon dioxide refrigeration unit has been started. The working fluid temperature flowing into the heat dissipation coil of the intermediate temperature section of the gas cooler 2-10 is above 70℃. Under the action of the generator heating pump, the cooling water flows into the generator heating water inlet 10-2 through the outlet e-2 of the intermediate temperature section of the gas cooler 2-10, the generator heating water inlet 10-2', and the electric regulating valve 1-15. While continuously absorbing heat from the working fluid, the cooling water continues to cool the intermediate temperature working fluid gas to below 50℃ and vaporizes the water in the negative pressure steam generator 1-10 into steam of about 6000Pa. The cooling water that has released the latent heat of vaporization flows back to the gas cooler through the generator heating water outlet 10-1, the heating water outlet electric valve 1-11, and the return water inlet e-1' of the gas-cooled intermediate temperature section. In the 2-10 medium-temperature section, one heating cycle of the negative pressure steam generator 1-10 is completed, and the cycle continues continuously until the process program is completed and then operation stops. Simultaneously with the cessation of the heating program in the negative pressure steam generator 1-10, the relevant valves of the heat recovery system are opened, allowing the system to recover the heat from the gas cooling 2-10 and maintain the normal operation of the transcritical carbon dioxide refrigeration unit. In fact, defrosting begins simultaneously with the heating process in the negative pressure steam generator 1-10. The negative pressure steam generated by the negative pressure steam generator 1-10 flows continuously into the freeze-drying chamber through the generator steam outlet 10-3, the generator steam electric valve 10-5, and the defrosting steam inlet d-2. Driven by the energy field, it diffuses onto the ice surface of the cold trap 1-30, interacting with the ice surface. The process involves heat exchange, releasing steam with latent heat of vaporization to melt the ice into water. This heat exchange continues until the set process time, at which point all the ice has melted, ending the defrosting process. The electric regulating valve 1-15 for heating water and the electric valve 1-11 for heating water outlet are then closed, stopping the negative pressure steam generator 1-10 from heating. The electric valve 7-1 for breaking the vacuum is opened to release the vacuum in the defrosting system. After pressure balance, the electric valve d-5 for defrosting drainage, the electric pump d-6 for defrosting drainage, and the electric valve 10-6 for generator water replenishment are opened to replenish water to the negative pressure steam generator 1-10. Once the set water level is reached, the electric valve 10-6 for generator water replenishment is closed, and the electric valve 5-1 for the recovery water tank inlet is opened to store all remaining defrosting water in the recovery water tank 5-10 for use in the defrosting water polishing system.At this point, the defrost drain valve pump is shut off, and the negative pressure defrost water recovery section (D) is complete.

[0026] The design principle of this invention: Regardless of the type of freeze dryer, the freeze-drying process inevitably requires refrigeration equipment to provide freezing and sublimation cooling capacity; heating equipment to provide sublimation and defrosting; and vacuum equipment to provide a vacuum environment. Furthermore, during the production of dried products, a large amount of raw material (fruit and vegetable raw materials > 80%) is dehydrated. Currently, traditional freeze dryers generally use HFC-based refrigeration equipment (CWP > 1000); the heating equipment is generally a boiler (COP < 1); and the defrosting solution is generally water defrosting. Therefore, traditional freeze dryers are extremely energy-intensive, wasteful, and environmentally unfriendly. This is highly incompatible with the current environment of "energy conservation, emission reduction, and green development," which is why this advanced drying technology cannot be widely adopted. The biggest pain point is that this invention selects the environmentally friendly CO2 working fluid (GWP=1), adopts a transcritical bipolar refrigeration compressor unit, and adds a segmented gas cooler 2-10, a subcooler 2-20, and a low-temperature circulation tank 2-30. It fully utilizes the excellent low-temperature refrigeration performance and transcritical temperature glide heat transfer characteristics of carbon dioxide, and achieves the effect of reverse Carnot cycle refrigeration and heating energy efficiency ratios both greater than 1. It combines the freeze-drying refrigeration and heating processes into one, enabling the freeze dryer's cooling equipment to perform dual functions of refrigeration and heating. Combined with the freeze dryer's heat recovery system (ZL202023232256.5), it eliminates the heating equipment and power consumption of COP<1, thereby producing a super efficiency of comprehensive COP>6. It utilizes the vacuum unit equipped in the freeze dryer and adds a negative pressure steam generator 1-10 (ZL 201620676267.7) and recovery water tank 5-10 (ZL202021599215.7), using the heat provided by the medium temperature section of gas cooler 2-10, completely melt the ice trap 1-30 (ZL201620676268.1), and fully recycle it, so that the utilization rate of freeze-dried raw materials is close to 100%.

[0027] This invention addresses the characteristics of freeze-drying processes by effectively utilizing the low-temperature cold source and high-temperature heat source generated by the transcritical carbon dioxide cycle. It adds a segmented gas cooler 2-10 to meet the heating requirements of the heating plate assembly 1-20 (ZL2016201385248.5) and the negative pressure steam generator 1-10. It uses a low-rate circulating working fluid tank 2-30 for direct evaporation to meet the low-temperature, uniform, and efficient refrigeration requirements of the cold trap 1-30 and the cold air blower 1-40. The addition of a subcooler 2-20 and an electric throttling valve 2-31 solves the problems of low carbon dioxide critical temperature (31.1℃) and large throttling losses. The addition of a negative pressure steam generator 1-10 and a recovery water tank 5-10 utilizes a vacuum unit to generate a negative pressure environment. Under negative pressure and low-temperature conditions, it fully utilizes the low-quality heat source in the medium-temperature range of the gas cooler 2-10 to achieve a fully self-melting process of ice and water without additional energy consumption, further improving the comprehensive utilization rate of resources and the purity of plant water.

[0028] The system control of this invention is achieved through a programmable PLC module + configuration host computer, 5G network + mobile terminal, and dedicated sensors and actuators at each control point to perform local and remote automatic program control of the system. The transcritical carbon dioxide refrigeration unit completes the cooling process of the air cooler 1-40 and cold trap 1-30, as well as the heating process of the heating plate group 1-20 and negative pressure steam generator 1-10. Through the negative pressure defrost water recovery system, the reuse of low-quality heat source in the medium temperature section of the air cooler and the complete recovery of ice melt water are realized, which improves the comprehensive utilization rate of resources and the purity of plant water, creating extremely high process value.

Claims

1. A process for carbon dioxide refrigeration and heating and negative pressure defrosting water recovery in a freeze dryer, characterized in that... The system includes a carbon dioxide heating section (A); a common section (B); a carbon dioxide refrigeration section (C); and a negative pressure defrosting water recovery section (D). The carbon dioxide heating section (A) consists of a gas cooler (2-10), a medium-temperature section inlet (e-1), a medium-temperature section outlet (e-2), a medium-temperature working gas outlet (e-3), a high-temperature working gas inlet (e-4), a high-temperature section inlet (e-5), a high-temperature section outlet (e-6), a high-pressure stage exhaust port (2-100) for the transcritical carbon dioxide refrigeration unit, a generator heating return water port (10-1'), and a generator heating... Hot water supply interface (10-2'), heating plate assembly (1-20), heating plate assembly outlet 1 (20-1), heating plate assembly outlet 2 (20-2), heating plate assembly inlet 1 (20-3), heating plate assembly inlet 2 (20-4), heating plate assembly inlet electric regulating valve (1-21), heating plate assembly heat medium pump (1-22), heating plate assembly electric valve (1-23), heating plate water supply tee (1-2a), heating plate water supply electric valve (1-24), heat recovery system water supply interface (1-200), heating plate assembly outlet electric valve (1-25), heating plate return... The system consists of a water tee (1-2b), a heating plate return water electric valve (1-26), and a heat recovery system return water interface (1-201); the common section (B) consists of a subcooler (2-20), a hot-side inlet (f-1), a cold-side outlet (f-2), a hot-side outlet (f-3), a cold-side inlet (f-4), and a low-pressure stage suction interface (2-200) for the transcritical carbon dioxide refrigeration unit; the carbon dioxide refrigeration section (C) consists of a low-pressure circulation tank (2-30), a steam inlet (g-1), a throttling gas inlet (g-2), a steam outlet (g-3), and a cryogenic liquid outlet (g- 4) Composed of cryogenic liquid outlet 2 (g-5), electric throttle valve (2-31), electric regulating valve (2-32), cold trap (1-30), cold trap inlet (30-2), cold trap outlet (30-1), cold trap electric regulating valve (1-31), cold trap working fluid circulation pump (1-32), cold trap outlet electric valve (1-33), air cooler (1-40), air cooler inlet (40-2), air cooler outlet (40-1), air cooler electric regulating valve (1-41), air cooler working fluid circulation pump (1-42), and air cooler outlet electric valve (1-43);The negative pressure defrosting water recovery section (D) consists of a negative pressure steam generator (1-10), a generator heating water outlet (10-1), a heating water outlet electric valve (1-11), a generator heating water inlet (10-2), a heating water inlet electric valve (1-15), an air-cooled medium-temperature return water interface (e-1'), an air-cooled medium-temperature supply water interface (e-2'), a generator steam outlet (10-3), a generator steam electric valve (10-5), a defrosting steam inlet (d-2), a generator water inlet (10-4), and a generator water inlet electric valve (10-15). -6) Composed of a defrost water tee (d-1b), defrost drain outlet (d-1), defrost drain electric valve (d-5), defrost drain pump (d-6), recovery water tank (5-10), recovery water tank inlet electric valve (5-1), recovery water tank outlet electric valve (5-2), recovery water purification interface (5-100), negative pressure suction port (d-3), negative pressure suction electric valve (3-1), vacuum unit interface (3-100), vacuum breaking port (d-7), vacuum breaking electric valve (7-1), and venting interface (7-100).

2. The method for carbon dioxide refrigeration and heating and negative pressure defrosting water recovery in a freeze dryer according to claim 1, characterized in that... The carbon dioxide heating section (A) of the transcritical carbon dioxide refrigeration unit has its high-pressure stage exhaust port (2-100) connected to the high-temperature working gas inlet (e-4) of the gas cooler (2-10). It is then connected to the medium-temperature working gas outlet (e-3) via the heat dissipation pipes of the high-temperature and medium-temperature sections of the gas cooler (2-10), and further connected to the hot-side inlet (f-1) of the common section (B) working fluid subcooler (2-20) via a pipeline. The high-temperature section outlet (e-6) of the gas cooler (2-10) is connected to the heating plate group inlet one (20-3) and heating plate group inlet two (20-4) via the heating plate water supply tee (1-2a), the heating plate group electric valve (1-23), the heating plate group heat medium pump (1-22), and the heating plate group inlet electric regulating valve (1-21). The other port of the heating plate water supply tee (1-2a) is connected to the heat recovery system via the heating plate water supply electric valve (1-24). The system water supply interface (1-200) is connected; the heating plate assembly outlet one (20-1) and heating plate assembly outlet two (20-2) are connected to the high-temperature section inlet (e-5) of the gas cooler (2-10) through the heating plate assembly outlet electric valve (1-25) and the heating plate return water tee (1-2b); the other interface of the heating plate return water tee (1-2b) is connected to the heat recovery system return water interface (1-25) through the heating plate return water electric valve (1-26). -201) are connected; the generator heating return water interface (10-1') of the medium temperature section inlet (e-1) of the gas cooler (2-10) and the generator heating water supply interface (10-2') of the medium temperature section outlet (e-2) are respectively connected to the air-cooled medium temperature return water interface (e-1') of the generator heating water outlet (10-1) and the air-cooled medium temperature water supply interface (e-2') of the generator heating water inlet (10-2) through pipeline valve pumps.

3. The process for carbon dioxide refrigeration and heating and negative pressure defrosting water recovery in a freeze dryer according to claim 1, characterized in that... The common part (B) subcooling (2-20) hot side inlet (f-1), cold side outlet (f-2), hot side outlet (f-3), and cold side inlet (f-4) are respectively connected to the medium temperature working gas outlet (e-3) of the carbon dioxide heating part (A); the low pressure stage suction port (2-200) of the carbon dioxide transcritical refrigeration unit, the electric throttle valve (2-31) and the electric regulating valve (2-32) of the carbon dioxide refrigeration part (C).

4. The process for carbon dioxide refrigeration and heating and negative pressure defrosting water recovery in a freeze dryer according to claim 1, characterized in that... The carbon dioxide refrigeration section (C) has its low-temperature circulation tank (2-30) with throttling gas inlet (g-2) and vapor outlet (g-3) connected to an electric throttling valve (2-31) and an electric regulating valve (2-32), respectively; the low-temperature liquid outlet (g-4) of the low-temperature circulation tank (2-30) is connected to the cold trap inlet (30-2) via the cold trap working fluid circulation pump (1-32) and the cold trap electric regulating valve (1-31); the cold trap outlet (30-1) is connected to the cold trap outlet (30-1) via a cold... The outlet electric valve (1-33) of the trap is connected to the steam inlet (g-1) of the low circulation tank (2-30); the low-temperature liquid outlet (g-5) of the low circulation tank (2-30) is connected to the inlet (40-2) of the cold air blower through the working fluid circulation pump (1-42) and the electric regulating valve (1-41) of the cold air blower; the outlet (40-1) of the cold air blower is connected to the steam inlet (g-1) of the low circulation tank (2-30) through the outlet electric valve (1-43) of the cold air blower.

5. The method for carbon dioxide refrigeration and heating and negative pressure defrosting water recovery in a freeze dryer according to claim 1, characterized in that... The negative pressure defrost water recovery section (D) has its generator heating water outlet (10-1) and generator heating water inlet (10-2) connected to the air-cooled medium-temperature return water interface (e-1') and air-cooled medium-temperature supply water interface (e-2') respectively via a heating water outlet electric valve (1-11) and a heating water electric regulating valve (1-15); the generator steam outlet (10-3) is connected to the defrost steam inlet (d-2) via a generator steam electric valve (10-5); and the defrost drain outlet (d-1) is connected to the defrost drain electric valve (d-5), defrost drain pump (d-6), and defrost water tee (d-1b). The generator water supply electric valve (10-6) is connected to the generator water supply port (10-4); the other port of the defrost water tee pipe d-1b is connected to the recovery water tank 5-10 through the recovery water tank inlet electric valve 5-1; the recovery water tank outlet electric valve 5-2 is connected to the recovery water polishing interface 5-100; the negative pressure suction port (d-3) is connected to the vacuum unit interface (3-100) through the negative pressure suction electric valve (3-1) and is connected to the defrost steam inlet (d-2) through the chamber; the negative pressure system vacuum breaking port (d-7) is connected to the venting interface (7-100) through the vacuum breaking electric valve (7-1).

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