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29
2022
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08
How to solve the problem of vacuum degree control in Wiped film molecular distillation
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Wiped film molecular distillation relies on the difference in the mean free path of molecular motion to achieve separation, and does not need to reach the boiling point of the material.
Wiped film molecular distillation relies on the difference in the mean free path of molecular motion to achieve separation, and does not need to reach the boiling point of the material. In addition, the operating vacuum of the distillation is relatively high, which further reduces the operating temperature.
Wiped film molecular distillation In the evaporation process, the material is forced to form a very thin liquid film and is pushed in a direction, so that the liquid residence time in the separator is very short. For example, light molecules condense as soon as they escape, and the heating time is short, usually a few seconds or ten seconds. In this way, the thermal damage of the material is very small, and the separation process of heat-sensitive substances provides operating conditions that cannot be compared with traditional distillation.
In terms of vacuum degree control, the early control method is to use open-loop control method. This control method has a large fluctuation phenomenon. To achieve higher purity requirements, in order to solve this problem and stabilize the vacuum degree at a predetermined value, a gas flow controller can be used for feedback control, and the purpose of maintaining a stable vacuum degree can be achieved by adjusting the air intake and air output.
If the vacuum degree control adopts closed-loop control, as long as the vacuum degree of the liquid ring vacuum pump and the rotary vane vacuum pump is maintained at a negative pressure, the vacuum degree of the distiller is kept stable by connecting the gas flow controller in series and using the gas flow controller.
Wiped film molecular distillation technology can improve the operational difficulties of common distillation environments. Since distillation only needs to be between the hot and cold sides, when the temperature difference is reached, separation can be carried out at different temperatures. The traditional distillation needs to strictly follow the boiling point of the material to carry out related operations, which is not only time-consuming and laborious, but also difficult to master.
Traditional distillation will cause bubbling and boiling at high temperature, and these problems can also be solved by distillation. Wiped film molecular distillation can evaporate freely on the surface of the liquid film, because its operating pressure is low, so there are no similar problems.
Wiped film molecular distillation technology can be applied to various substances, which cannot be achieved by ordinary distillation. Ordinary distillation needs to master the equilibrium dynamics between the liquid phase and the gas phase, but distillation has changed this situation. The heating time is short, as long as ten seconds. Productivity.
Wiped,film,molecular,distillation
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