Molecular distillation system is a distillation method operated under high vacuum. At this point, the average degree of freedom of vapor molecules is greater than the distance between the evaporation surface and the condensation surface, so the liquid mixture can be separated by the difference in evaporation rate between the material and liquid components.
The molecular distillation system is a special liquid separation technology that differs from traditional distillation separation principles by achieving separation through the difference in the average free path of molecular motion of different substances.
As the liquid mixture flows and heats along the heating plate, heavy molecules escape from the liquid surface and enter the gas phase. Due to the different free ranges of heavy molecules, the movement distance of molecules of different substances after escaping from the liquid surface is also different. If the condenser plate is set properly, light molecules will reach the condenser plate and be discharged, while heavy molecules will not achieve the purpose of being discharged along the mixture by the condenser plate. In this way, the purpose of material separation has been achieved. The pressure difference between the boiling film and the condensation surface is the driving force for steam flow, and a small pressure drop can cause steam flow. The distance between the boiling surface and the condensing surface is 1 mbar. A distiller based on this principle is called a short path distiller. The short-range distiller (molecular distillation) has a built-in condenser on the heating side, which reduces the working pressure to 0.001 mbar.
The molecular distillation system consists of an externally heated vertical cylinder, a central condenser, and a rotating scraper between the distiller and condenser.
The distillation process is as follows: the material is added from the top of the evaporator and continuously and evenly distributed on the heating surface through the liquid distributor on the rotor. Then, the scraper scrapes the liquid into a very thin, turbulent liquid film, which rotates downward in a spiral shape. During this process, light molecules escaping from the heated surface undergo a short circuit and almost no collision with the built-in condenser to condense into liquid. They flow down the condenser tube and are discharged through the outlet tube at the bottom of the evaporator. The residual liquid weight molecules in the circle below the heating zone are collected in the irregular channel and then flow out through the side outlet pipe.