According to the principle of molecular distillation separation, molecular distillation separation mainly relies on the difference in molecular mean free path between light molecules and heavy molecules. At the same time, the light molecules to be separated that escape during the separation process can be easily obtained by cooling. Lightweight recycling, so molecular distillation technology has the following basic characteristics:
(1) Cryogenic distillation far away from the boiling point of the compound. Conventional distillation technology mainly relies on the difference in boiling points between the compounds for separation. Therefore, to achieve efficient separation, the compound to be separated must be in a boiling state. Therefore, the separation process of the conventional distillation technology needs to be relatively high. High temperature. The molecular distillation separation technology relies on the difference in the mean free path of the molecular motion of the compound. The high vacuum distillation process can not only reduce the full point of the compound, but also further increase the difference in the mean free path between the compounds, so the distillation process can be Efficient distillation at low temperature.
(2) Distillation under ultra-low pressure. The theoretical molecular distillation separation process occurs between 0.01Pa and 0.1Pa. Ultra-low distillation pressure can increase the mean free path of molecular motion of compounds, thereby expanding the difference in mean free paths between compounds , To achieve efficient separation. The traditional distillation technology is mostly pot distillation. The compound to be separated is first vaporized into a gas at the boiling point. The gaseous compound is pumped out as a whole under the action of a vacuum pump, and can be condensed when it flows through the condenser. The distance between the condenser and the evaporation surface is too long, making this section
The distance between is full of gaseous compounds, so it is difficult to reduce the pressure at the evaporation liquid level. For molecular distillation technology, because the condenser and the evaporation surface are arranged very closely, once the compound to be separated volatilizes and escapes, it is immediately condensed. Therefore, the partial pressure of the gaseous compound between the condenser and the evaporator surface is very low. Compound separation at low pressure.
(3) Fast and efficient separation. In the process of molecular distillation, the compound to be separated flows in from the upper part of the separator body and flows out from the lower part. On the surface of the evaporator, the compound to be separated will form a liquid film with a thickness of about 2mm under the action of the film forming part. The liquid film-like distillation is conducive to the efficient escape of the compound to be separated. At the same time, in the molecular distillation separation process, the condensing surface and the evaporation surface are arranged close to each other, so that the compound to be separated can be quickly condensed once it escapes, thus reducing the residence time of the heat-sensitive compound to be separated at high temperature, which is conducive to keeping the compound characteristic. In general, molecular distillation technology can not only reduce the residence time of the compound to be separated on the heating surface, but also shorten the high-temperature gaseous residence time between the escape of volatiles and condensation.