From the description of the distillation process, attention should be paid to "specific pressure conditions" and "evaporation area condensation surface distance". It means that not all raw materials can achieve molecular distillation; the molecular distillation process can only be achieved in a scraped short-path distiller or a centrifugal short-path distiller; it is not simply the distillation in the short-path distiller, which is molecular distillation. The molecular distillation must be realized in a specific The molecular-level motion and separation process realized at a specific temperature under pressure.

Therefore, molecular distillation and short-path distillation cannot be simply conflated. The essence is different. Take the scraper type short-path distiller as an example, its special structure design allows the operating pressure to reach a very low operating vacuum. The vacuum of the experimental scale equipment can reach 0.001mbar, and even the industrial scale equipment can reach 0.01-0.05mbar.

Since the scraper type short-path distiller adopts the central condensation method, the evaporation area and the condensation surface distance are generally less than 50mm (the distance of the experimental device is less than 10mm), so that there is only a slight pressure drop between the evaporator and the condenser, which is also the vacuum at the end of the vacuum system Almost close to the vacuum of the evaporator. The design of DEA is fully in line with the realization conditions of the molecular distillation process.

By adopting a vertical rotating scraper to form a film, the residence time of the material on the heating wall is only ten seconds. Because there is a strict distance requirement between the heating wall of the short-path distillation and the condenser, the light molecules escaping from the liquid surface reach the condensation surface almost instantaneously, and the heating time of the light molecules in the vapor phase can be ignored in this process.

The short-path evaporator adopts a mechanical scraping film system, which is different from the uneven film formation defects of other falling film evaporators. The film thickness of the material in the short-path evaporator is uniform and the flow characteristics are excellent, because the area of the liquid surface and the heating surface are almost equal , Excellent mass and heat transfer efficiency.