-
E-mail
446637721@qq.com
-
Phone
15537136258
-
Address
Yingyu Industrial Zone, Gongyi City, Henan Province
Gongyi Yuhua Instrument Co., Ltd
Process principle of short-range molecular distillation equipment
Date: 2025-05-29Read: 6
The process principle of short-range molecular distillation equipment is based on the difference in molecular free path to achieve separation. Its process flow integrates high vacuum environment, short-range evaporation condensation, and high-efficiency film formation technology. The specific analysis is as follows:
1、 Core Separation Principle
1. Molecular free path difference
Under high vacuum conditions (usually below 10 Pa), molecules of different substances exhibit significant differences in their average free path (average distance traveled between two collisions) due to variations in molecular weight and velocity. Light molecules have a longer free path and can reach the condensation surface to be captured; Heavy molecules, due to their short free path, cannot reach the condensation surface and return to the evaporation zone to achieve component separation.
2. Short-range evaporation condensation mechanism
The distance between the evaporation surface and the condensation surface is usually smaller than the free path of light molecules (several centimeters to tens of centimeters), ensuring that light molecules can condense directly without collision after escaping, while heavy molecules are separated due to insufficient movement distance. This mechanism avoids the boiling process of traditional distillation and operates at temperatures much lower than the atmospheric boiling point of the material (usually 50-100 ℃ lower), making it suitable for thermosensitive substances.
2、 Key technical support
1. Vacuum system
Maintain the system pressure below 10 Pa through a vacuum pump group to reduce gas molecule collision interference, extend the molecular free path, and ensure separation efficiency.
2. Film formation and mass transfer optimization
Scraping technology: The rotor driven scraper evenly spreads the material into a thin liquid film of 0.1-0.5 mm, increasing the evaporation surface area and enhancing mass transfer, shortening the heating time of the material (usually only a few seconds).
Centrifugal film formation (advanced equipment): Utilizing centrifugal force to form a thinner and more uniform liquid film, further improving thermal conductivity efficiency.
3. Condensation control
The condensation surface temperature should be precisely lower than the condensation point of light components to ensure instantaneous capture of target molecules and avoid secondary evaporation.
3、 Process flow steps
1. Pre treatment and degassing
After preheating, the material enters the degassing system to remove dissolved gases and prevent bubbles from affecting the stability of the liquid film under high vacuum.
2. Evaporation condensation separation
The material enters the evaporator through a distributor, forming a thin liquid film and heating it to the set temperature;
Light molecules escape from the liquid surface directly to the condenser, while heavy components remain on the evaporation surface and are discharged;
The separated light components are condensed and recovered, while the heavy components enter the residual liquid collection system.
3. Dynamic parameter regulation
By real-time monitoring and adjustment of temperature, vacuum degree, and feed rate, optimize separation efficiency and prevent material thermal degradation.
4、 Technical advantages
1. Low temperature efficiency: avoid high temperature damage to thermosensitive ingredients (such as natural flavors and active ingredients in drugs);
2. High separation accuracy: capable of handling mixtures with boiling point differences less than 5 ℃;
3. Low energy consumption: The vacuum environment reduces the latent heat required for material vaporization and shortens the process cycle.
Typical applications include natural spice purification (such as rose essential oil, cinnamaldehyde), monomer removal of polymer materials, and purification of pharmaceutical intermediates.
Last Article: Working principle of circulating water vacuum pump
Next Article: Process principle of small rotary evaporator