molecular distillationIt is a distillation method operated under high vacuum, in which the average free path of vapor molecules is greater than the distance between the evaporation surface and the condensation surface, thereby utilizing the difference in evaporation rate of each component in the feed liquid to separate liquid mixtures.
The distillation process is as follows: the material is added from the top of the evaporator, and is continuously and uniformly distributed on the heating surface through the material liquid distributor on the rotor. Then, the scraper scrapes the material liquid into a very thin, turbulent liquid film and pushes it downwards in a spiral shape. During this process, the light molecules escaping from the heating surface are condensed into liquid on the built-in condenser through a short route and almost without collision, and then flow down the condenser tube and are discharged through the discharge tube located at the bottom of the evaporator; The residual liquid, i.e. heavy molecules, is collected in a circular channel under the heating zone and then flows out through the side discharge pipe.
Emergency situation handling:
Abnormal vacuum degree:
Pressure surge>20% set value: turn off heating → activate emergency vent valve → check if the replenishment of liquid nitrogen in the cold trap is interrupted.
Continuous leakage: Apply high vacuum grease to seal the interface and replace the FFKM perfluoroether rubber seal ring.
Material abnormality:
Boiling treatment: Immediately turn off the heating, inject cold nitrogen gas to reduce pressure, and strictly prohibit opening the equipment directly.
Crystallization blockage: Stop the equipment, inject hot water for circulation dissolution, and disable mechanical blockage.
Cleaning and maintenance:
Glass components: Soak in 5% dilute hydrochloric acid for 30 minutes to remove scale, rinse with pure water, and then rinse with ethanol.
Scrap film rotor: Check the wear of the silicon carbide coating every 500 hours, and calibrate if the axial deviation is greater than 0.1mm.
Vacuum pump: Replace the dedicated pump oil every month, and keep the oil level of the mechanical pump above 80% of the scale line.