Short Path Distillation

Molecular distillation is a distillation method operated under high vacuum. At this time, the average free path of vapor molecules is greater than the distance between evaporation surface and condensation surface, so the liquid mixture can be separated by using the difference of evaporation rate of each component in the feed liquid.

Molecular distillation is a special liquid-liquid separation technology. It is different from traditional distillation, which depends on the principle of boiling point difference separation, but on the difference of average free path of molecular motion of different substances.

Molecular distillation equipment

When the liquid mixture flows along the heating plate and is heated, light and heavy molecules will escape from the liquid surface and enter the gas phase. Due to the different free paths of light and heavy molecules, the molecules of different substances move different distances after escaping from the liquid surface. If a condensing plate can be properly set, the light molecules will be condensed and discharged when they reach the condensing plate, while the heavy molecules will not reach the condensing plate and be discharged along the mixed liquid. In this way, the purpose of material separation is achieved. The pressure difference between the boiling film and the condensing surface is the driving force of the steam flow direction. For a small pressure drop, it will cause the steam flow. Operating at 1mbar requires a very short distance between boiling surface and condensing surface. The distiller made based on this principle is called short-range distiller. The short range distiller (molecular distillation) has a built-in condenser opposite the heating surface and reduces the operating pressure to 0.001mbar.

The short range distiller is a process of thermal separation technology working under the pressure of 1 ~ 0.001 mbar. It has low boiling temperature and is very suitable for heat sensitive and high boiling point substances. Its basic composition: cylindrical cylinder with heating jacket, rotor and built-in condenser; A film scraper and an anti splash device are accurately installed on the fixed frame of the rotor. The built-in condenser is located in the center of the evaporator, and the rotor rotates between the cylindrical cylinder and the condenser