Short Range Molecular Distiller [Structure and Characteristics]
1. A short-range molecular distiller is a condenser installed inside the scraper evaporator. When the feed mixture is heated and a light substance molecule moves to a certain distance, it is condensed into a liquid and separated when it encounters the condenser, and the heavy substance flows down along the wall of the condenser. Due to the condensation of light matter vapor phase inside, the vacuum pressure drop is very small, which can maintain a high vacuum degree inside the equipment.
2.Extremely high vacuumThe special structural design of short-range distillation allows for extremely low operating pressure and vacuum. The vacuum of experimental scale equipment can reach 0.1Pa, and even industrial scale equipment can reach 1-5Pa.
3.The operating temperature is much lower than the boiling point of the materialDue to the use of central condensation in short-range distillation, the cross-sectional area of material flow is equal to the evaporation surface, resulting in only a slight pressure drop between the evaporator and condenser. This means that the vacuum degree at the end of the vacuum system is almost close to that of the evaporator. The extremely low working pressure ensures an extremely low distillation temperature, so short-range distillation is currently considered a mild distillation method.
4.Characteristics of molecular distillationThe separation of mixtures is achieved due to the different properties of the average free path of molecules escaping from the liquid surface, and does not require complete boiling. Therefore, the actual evaporation temperature of the material in the evaporator is slightly lower than the theoretical boiling point of the material under empty conditions. This is fundamentally different from distillation.
5.Short heating time for short-range distillation：
6By adopting a vertical scraper film formation design, the residence time of the material on the heating wall is short. For other distillations, the heating time is generally longer (more than 30 minutes or even tens of hours), while short-range distillation only takes a few seconds. Due to the strict distance requirement between the heating wall and the condenser in short-range distillation, light molecules escaping from the liquid surface almost instantaneously reach the condensation surface, and the heating time of vapor phase light molecules can be ignored in this process. The possibility of thermal decomposition is minimized.Superior mass and heat transfer efficiency:

Short range distillation adopts a mechanical scraping film system, which is different from other types of evaporators such as falling film evaporators with uneven film formation defects. In the short range evaporator, the material film thickness is uniform and the flow characteristics are excellent. Due to the almost equal area of the liquid surface and heating surface, the mass and heat transfer efficiency is superior.
The advantages of short-range distillation in practical applications
1. High vacuum, low distillation temperature, short residence time, high evaporation efficiency, continuous distillation process.
For the separation of high molecular weight, high boiling point, thermosensitive, and easily oxidizable materials, there are advantages that cannot be compared to conventional methods, resulting in high yields and better product quality.
3. Short range distillation not only effectively removes low molecular weight substances such as organic solvents and odors in liquids, but also selectively evaporates the target product to remove other impurities, making it a protector and returner of natural quality.
4. Short range distillation can achieve physical processes that traditional separation methods cannot, therefore, it is widely used as a means of deodorization, decolorization, and purification in the separation of some high-value materials.

5. The evaporator wall is self-cleaning, with minimal pollution and easy cleaning.