Integrated pre-concentrated continuous flow zero-gravity cryogenic freeze-drying method and system

Abstract

The application discloses a kind of integrated pre-concentration continuous flow zero-gravity low-temperature freeze-drying method and system, including raw material pre-concentration: original material is cooled and solvent removal is formed concentrated ice powder under vacuum, low-temperature environment;Intermediate temporary storage: concentrated ice powder is transferred to intermediate storage unit and is temporarily stored;Transport and feed: concentrated ice powder is transported to dynamic drying unit;Vacuum low-temperature drying: concentrated ice powder is sublimated and dried under vacuum condition, and freeze-dried powder is obtained;Continuous feeding: the volume in dynamic drying unit drops to design threshold, and transport and feed are executed, newly added concentrated ice powder and freeze-dried powder obtained by sublimation drying are mixed and vacuum low-temperature drying is continuously executed, when freeze-dried powder in dynamic drying unit reaches maximum, feeding is stopped;Finished product collection: freeze-dried powder in dynamic drying unit is collected using sealed container.The application solves the problems of long process cycle, high energy consumption and poor product quality of existing low-temperature freeze-drying.

Description

Technical Field

[0001] This invention relates to the field of high-end food plant extraction technology, and more specifically to an integrated pre-concentration continuous flow zero-gravity low-temperature freeze-drying method and system. Background Technology

[0002] Freeze-drying is a key drying technology for preserving the activity of heat-sensitive materials (such as biological products, high-end foods, and plant extracts). For liquid materials with low solid content, direct freeze-drying requires the removal of a large amount of water through sublimation, resulting in extremely long freeze-drying cycles, huge energy consumption, and poor economic efficiency. To address this issue, the industry typically adds a pre-concentration step before freeze-drying.

[0003] However, existing concentration and freeze-drying processes are mostly independent steps, requiring materials to be transferred between different devices. This not only results in a loose equipment layout and a large footprint, but also exposes materials to the external environment during the transfer process, posing risks of contamination, moisture absorption, and loss of active ingredients due to temperature fluctuations, making it difficult to achieve fully automated and continuous production.

[0004] In addition, some continuous freeze-drying systems have been disclosed in the prior art, but their energy efficiency problem remains prominent for materials with high initial moisture content; at the same time, their material conveying and drying methods have limited effect on improving the heat and mass transfer efficiency of the material, and it is difficult to achieve precise feedback control based on the drying state, which affects the uniformity and quality of the final product.

[0005] Even with designs that combine pretreatment and freeze-drying, ensuring that heat-sensitive materials are dried in a low-temperature, closed environment throughout the entire process, avoiding temperature rise, oxidation, and contamination during intermediate steps, remains a significant challenge. Furthermore, precisely matching the output properties (such as viscosity, temperature, and particle size) of the pretreatment equipment with the feeding requirements of the subsequent dynamic freeze dryer to achieve stable, efficient, and continuous feeding, rather than simply equipment docking, is another problem that current technologies have not adequately solved.

[0006] Therefore, how to deeply integrate efficient pre-concentration with dynamic freeze-drying processes to achieve a highly efficient, energy-saving, compact, and fully automated continuous freeze-drying process while ensuring the final quality of heat-sensitive materials is a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0007] In view of this, the present invention provides an integrated pre-concentrated continuous flow zero gravity low-temperature freeze-drying method and system, which solves the problems of long cycle, high energy consumption and poor product quality in existing low-temperature freeze-drying processes.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A continuous-flow zero-gravity cryogenic freeze-drying method with integrated pre-concentration includes the following steps: S1. Raw material pre-concentration: The raw material is simultaneously cooled and solvent removed by thin film evaporation in a low temperature and vacuum environment, so that the water in the material is directly sublimated or rapidly frozen to form solid concentrated ice powder. S2, Intermediate Storage: The concentrated ice powder obtained in step S1 is transferred to the intermediate storage unit for temporary storage; S3, Conveying and Feeding: Conveying the concentrated ice powder in the intermediate storage unit to the dynamic drying unit; S4. Vacuum low-temperature drying: Vacuum the dynamic drying unit and dynamically stir the concentrated ice powder inside to sublimate and dry the concentrated ice powder under vacuum conditions to obtain freeze-dried powder. S5. Continuous feeding: The volume of concentrated ice powder in the dynamic drying unit will decrease during continuous sublimation. When the volume decreases to the design threshold, step S3 is executed. The newly added concentrated ice powder in the dynamic drying unit is mixed with the freeze-dried powder obtained by sublimation drying and step S4 is continued. When the freeze-dried powder in the dynamic drying unit reaches the maximum value, feeding is stopped. S6. Finished product collection: Collect the freeze-dried powder in the dynamic drying unit using a sealed container.

[0010] The beneficial effects of the technical solution of the present invention are that by pre-concentrating the raw materials, the volume of the raw materials can be reduced and most of the moisture can be removed. The concentrated ice powder is temporarily stored in the intermediate storage unit, and the dynamic drying unit can continuously feed according to the volume change during the dynamic drying process, so as to realize continuous production and significantly reduce production energy consumption.

[0011] Preferably, the raw material pre-concentration in step S1 involves removing 60% to 80% of the water or solvent from the original material.

[0012] Preferably, the working pressure of the dynamic drying unit after vacuuming in step S4 is 100 ~ 200 Pa, and the working temperature is -20℃ ~ 20℃.

[0013] Preferably, in step S6, the freeze-dried powder is collected in a vacuum environment or under conditions of being filled with an inert protective gas.

[0014] This invention also provides an integrated pre-concentration continuous flow zero gravity cryogenic freeze-drying system for implementing the above-mentioned integrated pre-concentration continuous flow zero gravity cryogenic freeze-drying method, comprising: The pre-concentration unit includes a storage tank and a thin-film evaporator connected in sequence; the storage tank is used to store raw materials; the thin-film evaporator is rotatably connected to a stirring paddle to stir the raw materials and evaporate their moisture to form concentrated ice powder; An intermediate storage unit, comprising a storage tank, wherein the inlet of the storage tank is connected to the outlet of the thin-film evaporator to receive the concentrated ice powder; A dynamic drying unit includes a drying chamber and a vacuum cold trap; the inlet of the drying chamber is connected to the outlet of the storage tank, and a paddle is rotatably connected inside the drying chamber to stir the concentrated ice powder; the vacuum cold trap is connected to the drying chamber to collect sublimated water vapor and maintain the vacuum level inside the drying chamber. A vacuum collector, the inlet of which is connected to the outlet of the drying chamber to collect freeze-dried ice powder; A temperature control unit is used to regulate the system temperature.

[0015] Preferably, the discharge port of the storage tank is equipped with a first ball valve, which is connected to the inlet of the drying chamber via a sealed screw conveyor.

[0016] Preferably, a second ball valve is fixed at the discharge port of the drying chamber, and the second ball valve is connected to the vacuum receiver.

[0017] Preferably, it also includes a vacuum control unit, which is connected to the vacuum cold trap to maintain the vacuum environment of the thin film evaporator and the drying chamber.

[0018] Preferably, the system also includes a refrigeration unit, which is connected to the vacuum cold trap and the temperature control unit to regulate the low-temperature environment of the system.

[0019] Preferably, the outer walls of the thin-film evaporator, the storage tank, and the drying chamber are all fitted with jackets, and the jackets are filled with refrigerant or heat transfer oil. Multiple jackets are connected to the refrigeration unit.

[0020] As can be seen from the above technical solution, compared with the prior art, the present invention discloses an integrated pre-concentration continuous flow zero gravity low-temperature freeze-drying method and system, which has the following beneficial effects: 1. High Efficiency and Energy Saving: Liquid raw materials are directly converted into solid concentrated ice powder under vacuum and low temperature using a thin-film evaporator. This process combines the dual functions of concentration and pre-freezing, reducing the volume of the original material and thus significantly reducing the amount of water that needs to be sublimated in the subsequent vacuum freeze-drying stage. This significantly shortens the overall drying cycle and effectively reduces the energy consumption of vacuum and refrigeration. The concentrated ice powder has a low temperature and a large specific surface area, allowing it to directly and smoothly enter the dynamic drying unit, eliminating the need for a separate pre-freezing step and achieving integrated concentration and pre-freezing, thereby improving overall energy efficiency from the source.

[0021] 2. Superior Quality: By using a sealed screw conveyor to connect the storage tank and the drying chamber, and finally employing a vacuum receiver, the entire process from pretreatment to finished product collection is kept in a closed loop, avoiding the risks of contamination, moisture absorption, and temperature rise during material transfer. Simultaneously, the loose and porous structure of the concentrated ice powder is highly compatible with the tumbling drying mode of the dynamic drying unit, allowing the ice powder to quickly form a uniform fluidized state within the drying chamber. This greatly enhances heat and mass transfer. Combined with precise temperature control, it maximizes the protection of the activity of heat-sensitive components, ensuring the quality of the final product. This effect cannot be achieved by directly injecting liquid concentrate or using other pretreatment methods.

[0022] 3. Continuous, compact and highly automated: This invention integrates functions such as pre-concentration, temporary storage and transfer and dynamic drying, and realizes continuous material replenishment and dynamic drying through automatic control, forming a continuous and automated production process from raw materials to finished products. Compared with the layout of split equipment, the structure of this invention is more compact, reduces manual intervention and improves production efficiency and stability. Attached Figure Description

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

[0024] Figure 1 The present invention provides a flow chart of the drying method. Figure 2 This is a schematic diagram of the drying system layout provided by the present invention; Figure 3 This is a cross-sectional view of the drying chamber provided by the present invention.

[0025] Among them, 1-storage tank; 2-thin film evaporator; 3-storage tank; 4-drying chamber; 41-chamber body; 42-drying chamber jacket; 43-stirring shaft; 44-rotation motor; 45-revolution motor; 46-second ball valve; 47-drying chamber inlet; 5-vacuum collector; 6-vacuum cold trap; 7-vacuum control unit; 8-refrigeration unit; 9-temperature control unit. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention discloses an integrated pre-concentration continuous flow zero-gravity low-temperature freeze-drying method and system, which aims to solve the problems of discontinuous process, high energy consumption, long cycle and difficulty in automation in the freeze-drying process for low solid content heat-sensitive liquids in the prior art. The core is to deeply couple the efficient pre-concentration step with the dynamic continuous freeze-drying process, so as to realize seamless, closed and automated processing from raw liquid to dried product.

[0028] This embodiment of an integrated pre-concentration continuous flow zero-gravity cryogenic freeze-drying system includes a pre-concentration unit, an intermediate storage unit, a dynamic drying unit, a vacuum collector 5, and a temperature control unit 9. The pre-concentration unit includes a storage tank 1 and a thin-film evaporator 2 connected in sequence. The outlet of the storage tank 1 is sealed to the inlet of the thin-film evaporator 2. The storage tank 1 is used to store raw materials. A stirring paddle is rotatably connected inside the thin-film evaporator 2 to stir the raw materials and evaporate their moisture to form concentrated ice powder. Specifically, a cooling jacket is fitted on the outer wall of the thin-film evaporator 2 for low-temperature thin-film evaporation of the materials under vacuum conditions, directly outputting solid concentrated ice powder. The intermediate storage unit includes a storage tank 3, the inlet of which is connected to the outlet of the thin-film evaporator 2 to receive the concentrated ice powder. The storage tank 3 is equipped with a cooling jacket on its outer wall and is sealed to the outlet of the thin-film evaporator via an insulated pipeline. This jacket is used to temporarily store concentrated ice powder in a low-temperature, inert environment. The storage tank 3 has both insulation and cooling functions to maintain the stability of the concentrated ice powder within it. The storage tank 3 also serves as a buffer container for the dynamic drying unit. The dynamic drying unit includes a drying chamber 4 and a vacuum cold trap 6. The inlet of the drying chamber 4 is connected to the outlet of the storage tank 3 via a sealed conveying device. A paddle is rotatably connected inside the drying chamber 4 to agitate the concentrated ice powder. The vacuum cold trap 6 is connected to the drying chamber 4 to collect sublimated water vapor and maintain the vacuum level within the drying chamber 4. The inlet of the vacuum collector 5 is connected to the outlet of the drying chamber 4 to collect the freeze-dried ice powder. A temperature control unit 9 is used to regulate the system temperature. The pre-concentration unit, intermediate storage unit, and dynamic drying unit are connected via sealed pipelines, forming a fully closed, low-temperature, continuous processing system from raw material to drying.

[0029] It should be noted that a thin-film evaporator is a highly efficient evaporation device. Its working principle involves mechanically (e.g., using a rotating scraper) forcing the liquid to be processed into a thin film on the inner wall of the evaporator, and then rapidly heating and evaporating it under vacuum conditions. Due to the thin liquid film, high heat transfer efficiency, and short material residence time, this device is particularly suitable for the gentle concentration of heat-sensitive materials, effectively removing solvents or moisture while protecting the active ingredients.

[0030] Concentrated ice powder refers to a frozen material in powder or fine granule form, prepared by first removing some water from a raw material liquid through a pre-concentration step, and then freezing it. It is the direct raw material for sublimation drying in a dynamic drying chamber. Compared to ice blocks or ice flakes obtained by directly freezing the raw material liquid, concentrated ice powder, due to its lower water content, can significantly shorten the subsequent sublimation drying time and reduce energy consumption.

[0031] A drying chamber is a type of vacuum freeze-drying equipment that uses internal stirring and rotation, along with the airflow generated by the sublimation of the material itself, to allow materials entering the chamber to undergo vacuum low-temperature drying in a suspended or continuously tumbling state (i.e., zero gravity or microgravity), thereby enhancing heat and mass transfer efficiency. This dynamic drying method differs from traditional static shelf-type freeze drying, enabling more uniform heating of material particles and a shorter moisture escape path, thus significantly improving the drying rate and product uniformity.

[0032] like Figure 3 As shown, the drying chamber 4 includes a chamber body 41, which is conical in shape and has a drying chamber inlet 47 at its upper end. A stirring shaft 43 is provided inside the chamber body 41, and a self-rotating motor 44 and a revolution motor 45 are fixed at the top of the chamber body 41. The self-rotating motor 44 is connected to the stirring shaft 43 through a gear transmission assembly so that the stirring shaft 43 rotates around its own axis. The revolution motor 45 is connected to the stirring shaft 43 so that the stirring shaft 43 revolves around the conical inner wall of the chamber body 41. The drying chamber jacket 42 is fitted around the outer periphery of the chamber body 41.

[0033] The chamber can be pre-frozen. The refrigeration unit cools the silicone oil to -70°C using a compressor, and then pumps the low-temperature silicone oil into the drying chamber jacket, cooling the drying chamber temperature to -65°C or lower. After the material is made into frozen ice powder in the upstream process, the frozen ice powder is added into the chamber through the drying chamber inlet. Since the chamber has been pre-frozen to a low temperature, the added ice powder is prevented from melting. After the material is added, the stirring system starts and stirs according to the set revolution and rotation speeds, causing the material in the chamber to rotate continuously. The revolution motor drives the stirring shaft to rotate along the conical inner wall, and the rotation motor drives the stirring shaft to rotate along its own axis. Through the stirring of the rotation and revolution of the stirring shaft, hundreds of thousands of small ice particles are created during the drying process, and these small ice particles are allowed to fly in the air. The surface area for sublimation and heat exchange changes from the plane of the static dryer shelf to the three-dimensional surface area of ​​each small ice particle, thus greatly improving the sublimation efficiency and reducing the drying time to 1 / 5 or even more of the static freeze-drying technology.

[0034] To further optimize the above technical solution and ensure the airtightness of the concentrated ice powder during the conveying process between the storage tank and the drying chamber, a first ball valve is installed at the outlet of the storage tank 3. The first ball valve is connected to the inlet of the drying chamber 4 via a sealed screw conveyor. The sealed screw conveyor can be achieved by installing a sealed sleeve around the screw conveyor, with both ends of the sleeve sealed to the outlet of the storage tank and the inlet of the drying chamber, respectively.

[0035] In some other specific embodiments, a second ball valve 46 is fixed at the discharge port of the drying chamber 4, and the second ball valve 46 is connected to the vacuum receiver 5 through a vacuum pipeline.

[0036] To further optimize the above technical solution, a vacuum control unit 7 is also included. The vacuum control unit 7 is connected to the vacuum cold trap 6 to maintain the vacuum environment of the thin film evaporator 2 and the drying chamber 4. The vacuum control unit 7 can use a vacuum pump to perform vacuuming operations on the thin film evaporator 2 and the drying chamber 4.

[0037] To further optimize the above technical solution, a refrigeration unit 8 is also included, which is connected to a vacuum cold trap 6 and a temperature control unit 9 to regulate the low-temperature environment of the system.

[0038] Vacuum cold traps, vacuum control units, and refrigeration units are crucial auxiliary facilities necessary for achieving and maintaining a freeze-drying environment. The vacuum control unit extracts non-condensable gases from the drying chamber, establishing and maintaining the high vacuum environment required for sublimation. The vacuum cold trap, through its internal ultra-low temperature surface, efficiently captures water vapor sublimating from the material within the drying chamber, preventing water vapor from entering the vacuum pump and affecting its performance, and maintaining the pressure difference between the drying chamber and the vacuum cold trap to provide a continuous driving force for sublimation. The refrigeration unit provides the vacuum cold trap with powerful cooling capacity and can be used for pre-freezing of the raw materials in the initial stage. By integrating these auxiliary components, a complete, stable, and efficient vacuum cryogenic drying environment is constructed, ensuring the smooth progress of the freeze-drying process and the final product's drying quality.

[0039] To further optimize the above technical solution, the outer walls of the thin-film evaporator 2, the storage tank 3, and the drying chamber 4 are all fitted with jackets, which are filled with refrigerant or heat transfer oil. Multiple jackets are connected to the refrigeration unit 8. The low-temperature environment inside the thin-film evaporator 2, the storage tank 3, and the drying chamber 4 is maintained by the circulation of refrigerant or heat transfer oil within the jackets, in conjunction with the refrigeration of the refrigeration unit 8.

[0040] In this embodiment, an automatic control system is also included, which is used for automatic control of vacuum level, temperature and material conveying during the production process.

[0041] This embodiment of the integrated pre-concentration continuous flow zero-gravity low-temperature freeze-drying method includes the following steps: S1. Raw Material Pre-Concentration: The raw material is extracted from the storage tank and transported to the thin-film evaporator using a metering pump. The raw material is cooled to the concentration temperature by the temperature control unit. The thin-film evaporator maintains a vacuum and low-temperature environment, and part of the liquid in the material is rapidly frozen into ice powder. Under the stirring and centrifugation of the thin-film evaporator, the ice powder forms a flowing ice powder film along the inner wall of the thin-film evaporator, causing the water in it to evaporate rapidly, thus obtaining concentrated ice powder. This process only requires the material to be in a liquid state, does not require a deep low-temperature environment, and reduces the volume of the material through concentration.

[0042] The purpose of this step is to reduce the moisture content of the material entering the main drying process, thus reducing the workload by bringing the task forward and solving the problem of huge energy consumption caused by directly freeze-drying materials with high moisture content.

[0043] Specifically, the temperature control unit cools the refrigerant in the jacket of the thin-film evaporator to -60°C, pre-freezing the raw material into ice powder under low temperature conditions. Under the action of the vacuum control unit, the thin-film evaporator is kept in a vacuum environment, rapidly evaporating and removing 60-80% of the water or solvent in the raw material, thereby obtaining concentrated ice powder. The concentrated ice powder has a huge specific surface area, which is beneficial for subsequent sublimation drying.

[0044] S2, Intermediate Storage: The concentrated ice powder obtained in step S1 is transferred to the intermediate storage unit for temporary storage; the pre-concentrated ice powder is directly transported to the storage tank for temporary storage. This step serves as a connection and buffer. The temperature of the refrigerant in the storage tank jacket is regulated by the temperature control unit to ensure the biological stability of the concentrated ice powder in the storage tank.

[0045] S3. Conveying and feeding: Conveying the concentrated ice powder in the intermediate storage unit to the dynamic drying unit.

[0046] The automatic control system opens the first ball valve, and simultaneously, the sealed screw conveyor transports the concentrated ice powder to the drying chamber. The storage tank and the drying chamber are connected by a sealed screw conveyor, ensuring a sealed environment during the transfer of the concentrated ice powder. This closed conveying method avoids the risks of contamination and temperature rise during the transfer process.

[0047] S4. Vacuum low-temperature drying: The dynamic drying unit is evacuated and the concentrated ice powder inside is dynamically stirred, so that the concentrated ice powder is sublimated and dried under vacuum conditions to obtain freeze-dried powder.

[0048] Concentrated ice powder enters the drying chamber, and the vacuum control unit evacuates the drying chamber to maintain its working pressure at 100~200pa. The refrigeration unit starts up and works with the temperature control unit to maintain the working temperature inside the drying chamber at -20℃~20℃. The sublimated water vapor is captured as ice by the vacuum cold trap at -60℃ or below.

[0049] Sublimation is an endothermic process, requiring a continuous supply of heat to sustain. The -20℃ to 20℃ temperature range represents a balance between drying efficiency and product protection. Maintaining a temperature above -20℃ provides sufficient heat for sublimation, ensuring a reasonable drying rate. Simultaneously, limiting the upper temperature to 20℃ is particularly beneficial for heat-sensitive materials, effectively preventing melting, collapse, or deactivation of active ingredients due to excessive heat. Precise control of the jacket temperature enables efficient and gentle heating of the material within a safe temperature range.

[0050] The combined effect of pressure and temperature determines the sublimation rate and the state of the material. By simultaneously controlling these two parameters within their optimal ranges, the drying process can be precisely controlled, resulting in the highest drying efficiency and the best freeze-dried powder quality. This approach offers superior technical performance and greater process stability compared to limiting either parameter alone.

[0051] S5. Continuous feeding: The volume of concentrated ice powder in the dynamic drying unit will decrease during continuous sublimation. When the volume decreases to the design threshold, step S3 is executed. The newly added concentrated ice powder in the dynamic drying unit is mixed with the freeze-dried powder obtained by sublimation drying and step S4 is continued. When the freeze-dried powder in the dynamic drying unit reaches the maximum value, feeding is stopped.

[0052] The automatic control system monitors the material level in the dynamic drying chamber in real time. Once the material level drops to a preset value due to moisture sublimation, it automatically controls the screw conveyor to add new concentrated ice powder. Through this feedback-based continuous feeding mechanism, continuous feeding and dynamic drying of materials are achieved, breaking the batch operation limitations of traditional freeze-drying processes and significantly improving equipment utilization and production efficiency.

[0053] S6. Finished product collection: Collect the freeze-dried powder in the dynamic drying unit using a sealed container.

[0054] After a pre-set production batch is completed, a vacuum collector collects the dried freeze-dried powder in a vacuum environment or under conditions of inert protective gas (such as nitrogen). This step completely isolates the dried, highly porous, and hygroscopic freeze-dried powder from external moisture and oxygen, thereby helping to maintain the final quality and shelf life of the freeze-dried powder.

[0055] Traditional drying processes often require breaking the vacuum at the discharge stage, exposing the material to air. This can severely impact the quality of highly hygroscopic or easily oxidized products. However, by adding a vacuum collector, the dried freeze-dried powder can be directly collected into a sealed container while maintaining a vacuum within the drying chamber or using inert gas for protection. This design not only avoids secondary contamination, moisture absorption, and oxidation of the finished product, ensuring its quality and stability, but also creates a complete closed loop in the production process, improving the system's automation level and operational safety.

[0056] In some other specific embodiments, the drying process may include an annealing step: that is, in the early stage of the main drying, the material temperature is briefly raised to a certain temperature (such as -10°C) below the eutectic point and above the glass transition temperature and held for a period of time to optimize the ice crystal structure and improve the subsequent sublimation rate before entering the conventional sublimation drying process.

[0057] Example 1 The present invention employs an integrated pre-concentration continuous flow zero-gravity low-temperature freeze-drying method and system to process heat-sensitive sea buckthorn juice.

[0058] Take 200L of sea buckthorn juice concentrate with an initial solid content of 12% (w / w) and a vitamin C content of 50mg / 100g. Start the system and evacuate the thin-film evaporator 2, storage tank 3, drying chamber 4, and corresponding connecting pipelines via the vacuum control unit 7. Cool the jacket of the thin-film evaporator 2 to a suitable temperature using the temperature control unit 9. Pump the sea buckthorn juice concentrate into the thin-film evaporator 2 at a flow rate of 50L / h for pre-concentration under vacuum to obtain a concentrated liquid. Then, prepare concentrated ice powder with a solid content of 40% in a low-temperature environment. This process removes approximately 70% of the water. The concentrated ice powder is temporarily stored in the storage tank 3.

[0059] Concentrated ice powder is intermittently fed into drying chamber 4 at a rate of 5 kg / h via a sealed screw conveyor. The initial vacuum degree of drying chamber 4 is evacuated to 100 Pa by vacuum control unit 7, and the temperature of vacuum cold trap 6 is maintained at -75℃ by refrigeration unit 8. The heating program of the jacket of drying chamber 4 is set to linearly rise from -50℃ to 0℃ within 0-2 hours and maintain at 0℃ until drying is complete. During the drying process, when the material level in the chamber falls below the set threshold, the automatic control system instructs the screw conveyor to replenish new concentrated ice powder. After all materials have been processed, the finished product is collected by vacuum collector 5 while maintaining vacuum. The entire process (from feeding to collection) takes approximately 8 hours. The final sea buckthorn freeze-dried powder has a final moisture content of 1.8%, a vitamin C content of 48.5 mg / 100g (based on reconstitution), and an activity retention rate as high as 97%. The product is golden yellow, reconstitutes rapidly (less than 3 seconds), and the solution is clear.

[0060] In contrast, the same sea buckthorn juice as in this example was processed using a traditional separate vacuum concentration and static tray freeze-drying process. First, 200L of the concentrate was pumped into a separate vacuum concentration tank and concentrated to a solid content of 40%, taking 4 hours. Then, the concentrate was manually removed and dispensed into multiple trays at room temperature, a process that took approximately 2 hours, during which the material was exposed to air for a considerable period. Subsequently, the trays were placed in a static shelf freeze dryer for pre-freezing, main drying, and desorption drying, taking a total of 18 hours. The entire traditional process took 24 hours. The resulting sea buckthorn freeze-dried powder had a moisture content of 2.5%, a vitamin C content of 40mg / 100g (after reconstitution), and an activity retention rate of only 80%. The product was dark in color and reconstituted slowly (greater than 60 seconds).

[0061] As can be seen, compared with the traditional process, the embodiments of the present invention improve production efficiency by 66.7% (reducing 24 hours to 8 hours), significantly enhance the protection of key active ingredients in the product, and achieve fully enclosed, continuous, and automated production, avoiding the risks of manual transfer and material exposure, saving manpower, and ultimately resulting in better quality indicators such as the degree of dryness and reconstitution of the product.

[0062] Compared to traditional separate processes, this invention not only significantly reduces processing time, but its core advantage lies in its integrated, fully enclosed, low-temperature treatment, which minimizes the oxidation and degradation of heat-sensitive components (such as vitamin C) in sea buckthorn juice during transfer, waiting, and exposure, thereby achieving an activity retention rate of up to 97%. This demonstrates that this invention is not simply a connection of equipment, but a holistic solution designed specifically for the characteristics of heat-sensitive materials, capable of generating a synergistic protective effect.

[0063] This invention is not only applicable to the food industry but also to the biopharmaceutical industry, where more stringent process conditions are required. It integrates a pre-concentration unit using a thin-film evaporator, an intermediate storage unit using a sealed screw conveyor, and a dynamic drying unit using a zero-gravity freeze dryer. Combined with a continuous feeding automatic control system based on level feedback, this creates a complete continuous freeze-drying solution from raw material liquid to dried finished product. This solution not only significantly improves production efficiency and reduces energy consumption but also helps protect the active ingredients of heat-sensitive materials through a fully enclosed, low-temperature, and rapid process, resulting in high-quality products. It solves the problems of discontinuous processes and high energy consumption in existing technologies, providing a highly efficient drying technology solution for related fields.

[0064] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0065] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A continuous flow zero-gravity low-temperature freeze-drying method with integrated pre-concentration, characterized in that, Includes the following steps: S1. Raw material pre-concentration: The raw material is simultaneously cooled and solvent removed by thin film evaporation in a low temperature and vacuum environment, so that the water in the material is directly sublimated or rapidly frozen to form solid concentrated ice powder. S2, Intermediate Storage: The concentrated ice powder obtained in step S1 is transferred to the intermediate storage unit for temporary storage; S3, Conveying and Feeding: Conveying the concentrated ice powder in the intermediate storage unit to the dynamic drying unit; S4. Vacuum low-temperature drying: Vacuum the dynamic drying unit and dynamically stir the concentrated ice powder inside to sublimate and dry the concentrated ice powder under vacuum conditions to obtain freeze-dried powder. S5. Continuous feeding: The volume of concentrated ice powder in the dynamic drying unit will decrease during continuous sublimation. When the volume decreases to the design threshold, step S3 is executed. The newly added concentrated ice powder in the dynamic drying unit is mixed with the freeze-dried powder obtained by sublimation drying and step S4 is continued. When the freeze-dried powder in the dynamic drying unit reaches the maximum value, feeding is stopped. S6. Finished product collection: Collect the freeze-dried powder in the dynamic drying unit using a sealed container.

2. The integrated pre-concentration continuous flow zero-gravity low-temperature freeze-drying method according to claim 1, characterized in that, The raw material pre-concentration in step S1 is to remove 60% to 80% of the water or solvent from the original material.

3. The integrated pre-concentration continuous flow zero-gravity low-temperature freeze-drying method according to claim 1, characterized in that, In step S4, the working pressure of the dynamic drying unit after vacuuming is 100 ~ 200 Pa, and the working temperature is -20℃ ~ 20℃.

4. The integrated pre-concentration continuous flow zero-gravity low-temperature freeze-drying method according to claim 1, characterized in that, In step S6, the freeze-dried powder is collected under vacuum or inert protective gas conditions.

5. A continuous flow zero-gravity cryogenic freeze-drying system with integrated pre-concentration, characterized in that, A continuous flow zero-gravity cryogenic freeze-drying method for implementing an integrated pre-concentration method as described in any one of claims 1 to 4, characterized in that it comprises: The pre-concentration unit includes a storage tank (1) and a thin-film evaporator (2) connected in sequence; the storage tank (1) is used to store raw materials; the thin-film evaporator (2) is rotatably connected to a stirring paddle to stir the raw materials and evaporate their moisture to form concentrated ice powder; An intermediate storage unit, comprising a storage tank (3), wherein the inlet of the storage tank (3) is connected to the outlet of the thin film evaporator (2) to receive the concentrated ice powder; The dynamic drying unit includes a drying chamber (4) and a vacuum cold trap (6); the inlet of the drying chamber (4) is connected to the outlet of the storage tank (3), and a paddle is rotatably connected inside the drying chamber (4) to stir the concentrated ice powder; the vacuum cold trap (6) is connected to the drying chamber (4) to collect sublimated water vapor and maintain the vacuum level inside the drying chamber (4); Vacuum collector (5), the inlet of which is connected to the outlet of the drying chamber (4) to collect freeze-dried ice powder; Temperature control unit (9) is used to regulate the system temperature.

6. The integrated pre-concentration continuous flow zero-gravity cryogenic freeze-drying system according to claim 5, characterized in that, The discharge port of the storage tank (3) is equipped with a first ball valve, which is connected to the inlet of the drying chamber (4) via a sealed screw conveyor.

7. The integrated pre-concentration continuous flow zero-gravity cryogenic freeze-drying system according to claim 6, characterized in that, The discharge port of the drying chamber (4) is fixed with a second ball valve, which is connected to the vacuum receiver (5).

8. The integrated pre-concentration continuous flow zero-gravity cryogenic freeze-drying system according to claim 5, characterized in that, It also includes a vacuum control unit (7), which is connected to the vacuum cold trap (6) to maintain the vacuum environment of the thin film evaporator (2) and the drying chamber (4).

9. The integrated pre-concentration continuous flow zero-gravity cryogenic freeze-drying system according to claim 5, characterized in that, It also includes a refrigeration unit (8), which is connected to the vacuum cold trap (6) and the temperature control unit (9) to regulate the low temperature environment of the system.

10. The integrated pre-concentration continuous flow zero-gravity cryogenic freeze-drying system according to claim 9, characterized in that, The outer walls of the thin film evaporator (2), the storage tank (3) and the drying chamber (4) are all fitted with jackets, and the jackets are filled with refrigerant or heat transfer oil. Multiple jackets are connected to the refrigeration unit (8).

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