Low-temperature quick-freezing freeze-drying system
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Solution Overview
Problem
Current freeze-drying technologies are inefficient and costly due to high energy consumption, complex operations, and limited processing capacity, especially for heat-sensitive materials, as they require separate quick-freezing and drying chambers and rely on expensive refrigerants like liquid nitrogen or inefficient two-stage compression refrigeration.
Innovation Solution
A low-temperature quick-freezing freeze-drying system with a refrigeration circulation loop, a quick-freezing/freeze-drying circulation loop, and a desorption drying circulation loop, utilizing heat exchangers with cold storage and air forcible circulation to enhance heat exchange efficiency and integrate quick-freezing and drying processes, reducing energy consumption and equipment complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum freeze-drying technology is used to preserve heat-sensitive materials, then the nutritional ingredients can be stored for more than 90%, but the initial investment of the device is relatively large and the system has small processing capacity
Solution Approach 1:
The drying process is divided into two distinct stages: sublimation drying (first stage) and desorption drying (second stage). Each stage operates with optimized parameters - the first stage uses low temperature and vacuum for ice crystal sublimation, while the second stage uses higher temperature for bound water removal. This segmentation allows the system to handle larger volumes efficiently while maintaining preservation quality.
Solution Approach 2:
The system dynamically adjusts temperature and pressure parameters between the two drying stages. In the first stage, low temperature and vacuum conditions favor sublimation. In the second stage, temperature is increased to overcome adsorption energy and remove bound water. These parameter changes enable the system to achieve both high preservation rates and increased processing capacity.
2Reliability
If separate quick-freezing and drying chambers are used, then the freeze-drying process can be performed, but the quick-freezing house must be separately constructed which increases the freeze-drying cost
Solution Approach 1:
The patent combines the quick-freezing function and drying function into a single integrated chamber. The same chamber serves both purposes: first as a freezing chamber where materials are rapidly frozen, then as a drying chamber where vacuum sublimation and desorption drying occur. This eliminates the need for a separate quick-freezing house, reducing equipment complexity and construction costs while maintaining process quality.
Solution Approach 2:
The drying chamber is designed to perform multiple functions: it serves as both the freezing chamber and the drying chamber. The chamber can operate under different pressure and temperature conditions to achieve different functions - rapid freezing when sealed, and vacuum drying when connected to the vacuum system. This multi-functionality reduces the number of separate equipment pieces needed.
3Productivity
If electric heating or steam heating is used in the desorption process, then bound water can be removed, but additional energy consumption of the system results
Solution Approach 1:
The system uses the heat of compression from the refrigeration compressor itself to provide the heating needed for desorption drying. The compressor's exhaust heat, which would otherwise be wasted, is directed to heat the materials during the second drying stage. This self-service approach eliminates the need for separate electric heating or steam heating systems, significantly reducing additional energy consumption while maintaining high drying efficiency.
Solution Approach 2:
The system converts the harmful waste heat from the compressor into a beneficial heating source for the desorption process. The high-temperature exhaust gas from the compressor, which would normally be discarded, is instead used to provide the necessary heat to remove bound water from materials. This transforms a harmful energy loss into a useful resource, reducing overall energy consumption.
4Temperature
If two-stage compression refrigeration is used to achieve low temperature, then cooling can be provided, but the refrigerant return air cooling capacity cannot be effectively recovered and the cooling efficiency is limited
Solution Approach 1:
The system performs preliminary cooling of the refrigerant in the evaporator before compression, and then recovers this cooling capacity by using the cold refrigerant to pre-cool the materials or the chamber before the main freezing process. This preliminary action maximizes the utilization of the refrigeration cycle's cooling capacity, effectively recovering what would otherwise be lost cooling energy.
Solution Approach 2:
The system recovers the cooling capacity from the refrigerant return air that would normally be discarded. The cold refrigerant returning from the evaporator is used to pre-cool the chamber or materials, or to cool other components of the system. This recovery of discarded cooling capacity significantly improves overall cooling efficiency and reduces energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves rapid cooling and efficient freeze-drying with high integration, miniaturization, simplicity, and energy savings, effectively preserving heat-sensitive materials while reducing energy costs and equipment complexity.
Implementation Method 1
The system adopts the heat exchangers with a cold storage function, so that the refrigeration capacity of the compressor is stored and used intensively to achieve rapid cooling of the materials.
Implementation Method 2
utilizing heat exchangers with cold storage and air forcible circulation to enhance heat exchange efficiency
Implementation Method 3
In such process, the drying of the materials mainly depends on the sublimation of ice crystals
Implementation Method 4
The second stage of drying aims to remove some of the bound water existing in products due to the mechanism of adsorption or the like
Implementation Method 5
sufficient heat must be supplied to desorb the bound water
Implementation Method 6
a high pressure refrigerant outlet of the compressor unit is connected to a refrigerant high pressure inlet of the first heat exchanger
Data Source
AI summary
A low-temperature quick-freezing freeze-drying system provided by the invention includes: a compressor unit, a first heat exchanger, an air cooler, a second heat exchanger, a throttling element, a third heat exchanger, a circulating fan, a drying chamber, a third valve, a fourth valve and connecting pipelines, and the above elements form a refrigeration circulation loop, a quick freezing/freeze-drying circulation loop, and a desorption drying circulation loop, thereby realizing the low-temperature quick-freezing and freeze-drying of materials. The invention adopts the heat exchangers with a cold storage function, so that the refrigeration capacity of the compressor is stored and used intensively to achieve rapid cooling of the materials.