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What is the working principle of a pure electric low-temperature falling film energy-saving evaporat
source：www.sjbyj.com Release time：2026-07-01
This device integrates two core technologies: vacuum falling film evaporation and electrically driven closed heat pump cold and hot cycle. It only uses electrical energy throughout the process and does not require an external steam boiler. It achieves negative pressure low-temperature concentration and recovers the latent heat of secondary steam to save energy. It is divided into three parts: falling film material evaporation system, electric heat pump cold and hot cycle system, and vacuum and separation system, which operate in coordination.
1、 Foundation: Low temperature evaporation material process with falling film (main line of material concentration)
1. Uniform film distribution
The concentrated liquid is pumped into the high-precision liquid distributor at the top of the evaporator through the feed pump, and evenly sprayed onto the inner wall of the vertical heat exchange tube; Under the combined action of gravity and secondary steam pulling downwards inside the tube, an ultra-thin continuous liquid film of 0.1-0.5mm thickness is formed on the tube wall, flowing from top to bottom without liquid static pressure accumulation, and without local overheating.
2. Negative pressure low-temperature vaporization
The vacuum pump continuously maintains high negative pressure (-0.085~-0.096MPa) in the evaporation chamber, significantly reducing the boiling point of water/solvent, and stabilizing the evaporation temperature at 35-65 ℃.
The outer wall of the heat exchange tube is provided with a low-temperature heat source of 45-80 ℃ by an electric heat pump. The heat quickly penetrates the tube wall to heat the thin liquid film, and the solvent vaporizes instantly to generate secondary steam; The material liquid stays for only 5-30 seconds, and the thermosensitive material will not undergo high-temperature decomposition, discoloration, or deactivation.
3. Vapor liquid separation cycle
The liquid film flows downwards to the bottom of the equipment, and the vaporized secondary steam enters the centrifugal demister separator together with the unevaporated concentrated liquid:
Concentrated solution: A portion of the circulating pump is pumped back to the top for further film evaporation and concentration, and the material is continuously discharged after reaching the set concentration;
Secondary steam: After removing the entrained liquid droplets, all of them are sent to the electric heat pump condenser to recover latent heat.
2、 Core energy-saving: Pure electric closed heat pump cold and hot cycle (whole machine energy consumption unit)
The entire set of heat and cold sources is realized by an electrically driven compressor and a closed cycle of refrigerant, with bidirectional recovery of cold and heat, which is the key to distinguishing traditional steam falling film. The cycle operates in four closed-loop steps:
1. Compression heat release (heating and evaporation of feed liquid)
The compressor performs pure electric work, compressing low-temperature and low-pressure refrigerant vapor into high-temperature and high-pressure gas, and sending it into the evaporator jacket heat exchange chamber; The refrigerant releases latent heat of condensation into the liquid inside the tube, providing all the heat source for falling film evaporation and self cooling liquefaction.
2. Throttle cooling (producing secondary steam for condensing cold source)
The high-temperature and high-pressure liquid refrigerant is throttled and depressurized through an expansion valve, becoming a low-temperature and low-pressure gas-liquid mixture refrigerant.
3. Heat absorption condensation (recovering secondary steam heat)
Low temperature refrigerant enters the condenser and exchanges heat with the high-temperature secondary steam generated by the feed liquid
Secondary steam releases latent heat and condenses into clean condensate water (solvent recovery); The refrigerant absorbs heat and completely vaporizes into low-temperature and low-pressure steam.
4. Cycle back and forth
After absorbing heat, the low-temperature refrigerant vapor is sucked back into the compressor, compressed and heated again, completing the cold and hot closed loop.
Energy saving logic
Traditional evaporators burn steam for heating while cooling water takes away secondary steam heat, resulting in complete waste of latent heat;
Pure electric motor type secondary steam latent heat is 100% recovered and reused as an evaporative heat source, consuming only a small amount of electrical energy from the compressor. The heating performance coefficient COP can reach 10-12, and evaporating 1 ton of water only consumes 12-18kWh of electricity, reducing energy consumption by more than 70% compared to single effect steam evaporators.
3、 Principle of vacuum assisted system
The liquid ring vacuum pump continuously extracts non condensable gas from the system and maintains a stable negative pressure
Reduce the boiling point of the feed liquid to achieve low-temperature and mild evaporation;
Increase the temperature difference between the inside and outside of the tube to improve the efficiency of falling film heat transfer;
Prevent solvent oxidation at high temperatures, suitable for organic solvents, traditional Chinese medicine extracts, food juices, etc.
4、 One sentence summary of the complete and continuous process of the whole machine
Liquid feeding → Top film forming ultra-thin falling film → Electric heat pump providing low-temperature heat source for negative pressure vaporization → Bottom gas-liquid separation, concentrated liquid circulation for concentration and discharge; The secondary steam enters the heat pump condenser for heat release, condensation, and recovery. The refrigerant is continuously supplied with cold and heat through an electric compression cycle, consuming only the electrical energy of the compressor and pump throughout the process, without steam or a large amount of water consumption in the cooling tower.
5、 Corresponding explanation of the advantages of the three core principles
Falling film structure: thin liquid film, short residence time, high heat transfer efficiency, and less prone to scaling;
Vacuum low temperature: 35-65 ℃ low temperature concentration, protecting the activity of thermosensitive materials;
Pure electric heat pump closed cycle: cold and hot energy recycling, zero steam consumption, significant energy saving, suitable for boiler free plant areas.
1、 Foundation: Low temperature evaporation material process with falling film (main line of material concentration)
1. Uniform film distribution
The concentrated liquid is pumped into the high-precision liquid distributor at the top of the evaporator through the feed pump, and evenly sprayed onto the inner wall of the vertical heat exchange tube; Under the combined action of gravity and secondary steam pulling downwards inside the tube, an ultra-thin continuous liquid film of 0.1-0.5mm thickness is formed on the tube wall, flowing from top to bottom without liquid static pressure accumulation, and without local overheating.
2. Negative pressure low-temperature vaporization
The vacuum pump continuously maintains high negative pressure (-0.085~-0.096MPa) in the evaporation chamber, significantly reducing the boiling point of water/solvent, and stabilizing the evaporation temperature at 35-65 ℃.
The outer wall of the heat exchange tube is provided with a low-temperature heat source of 45-80 ℃ by an electric heat pump. The heat quickly penetrates the tube wall to heat the thin liquid film, and the solvent vaporizes instantly to generate secondary steam; The material liquid stays for only 5-30 seconds, and the thermosensitive material will not undergo high-temperature decomposition, discoloration, or deactivation.
3. Vapor liquid separation cycle
The liquid film flows downwards to the bottom of the equipment, and the vaporized secondary steam enters the centrifugal demister separator together with the unevaporated concentrated liquid:
Concentrated solution: A portion of the circulating pump is pumped back to the top for further film evaporation and concentration, and the material is continuously discharged after reaching the set concentration;
Secondary steam: After removing the entrained liquid droplets, all of them are sent to the electric heat pump condenser to recover latent heat.
2、 Core energy-saving: Pure electric closed heat pump cold and hot cycle (whole machine energy consumption unit)
The entire set of heat and cold sources is realized by an electrically driven compressor and a closed cycle of refrigerant, with bidirectional recovery of cold and heat, which is the key to distinguishing traditional steam falling film. The cycle operates in four closed-loop steps:
1. Compression heat release (heating and evaporation of feed liquid)
The compressor performs pure electric work, compressing low-temperature and low-pressure refrigerant vapor into high-temperature and high-pressure gas, and sending it into the evaporator jacket heat exchange chamber; The refrigerant releases latent heat of condensation into the liquid inside the tube, providing all the heat source for falling film evaporation and self cooling liquefaction.
2. Throttle cooling (producing secondary steam for condensing cold source)
The high-temperature and high-pressure liquid refrigerant is throttled and depressurized through an expansion valve, becoming a low-temperature and low-pressure gas-liquid mixture refrigerant.
3. Heat absorption condensation (recovering secondary steam heat)
Low temperature refrigerant enters the condenser and exchanges heat with the high-temperature secondary steam generated by the feed liquid
Secondary steam releases latent heat and condenses into clean condensate water (solvent recovery); The refrigerant absorbs heat and completely vaporizes into low-temperature and low-pressure steam.
4. Cycle back and forth
After absorbing heat, the low-temperature refrigerant vapor is sucked back into the compressor, compressed and heated again, completing the cold and hot closed loop.
Energy saving logic
Traditional evaporators burn steam for heating while cooling water takes away secondary steam heat, resulting in complete waste of latent heat;
Pure electric motor type secondary steam latent heat is 100% recovered and reused as an evaporative heat source, consuming only a small amount of electrical energy from the compressor. The heating performance coefficient COP can reach 10-12, and evaporating 1 ton of water only consumes 12-18kWh of electricity, reducing energy consumption by more than 70% compared to single effect steam evaporators.
3、 Principle of vacuum assisted system
The liquid ring vacuum pump continuously extracts non condensable gas from the system and maintains a stable negative pressure
Reduce the boiling point of the feed liquid to achieve low-temperature and mild evaporation;
Increase the temperature difference between the inside and outside of the tube to improve the efficiency of falling film heat transfer;
Prevent solvent oxidation at high temperatures, suitable for organic solvents, traditional Chinese medicine extracts, food juices, etc.
4、 One sentence summary of the complete and continuous process of the whole machine
Liquid feeding → Top film forming ultra-thin falling film → Electric heat pump providing low-temperature heat source for negative pressure vaporization → Bottom gas-liquid separation, concentrated liquid circulation for concentration and discharge; The secondary steam enters the heat pump condenser for heat release, condensation, and recovery. The refrigerant is continuously supplied with cold and heat through an electric compression cycle, consuming only the electrical energy of the compressor and pump throughout the process, without steam or a large amount of water consumption in the cooling tower.
5、 Corresponding explanation of the advantages of the three core principles
Falling film structure: thin liquid film, short residence time, high heat transfer efficiency, and less prone to scaling;
Vacuum low temperature: 35-65 ℃ low temperature concentration, protecting the activity of thermosensitive materials;
Pure electric heat pump closed cycle: cold and hot energy recycling, zero steam consumption, significant energy saving, suitable for boiler free plant areas.
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