Laboratory membrane distillation deviceIt is a precision equipment used for separating liquid mixtures, particularly suitable for purifying high boiling point and thermosensitive substances. The core principle is to achieve rapid separation of light and heavy components under vacuum conditions by forming a uniform liquid film. The device usually consists of a thin film evaporator, a distillation column, a condensation system, a vacuum system, and a temperature control system. The material forms a thin film on the inner wall of the evaporator, and after being heated, the low boiling point components evaporate. They are further separated by a distillation column and collected after condensation.
Operation steps:
Preparation before the experiment:
Device inspection: Confirm that all pipelines (oil pipes, condensate pipes, vacuum pipes) are sealed properly and have no leaks; Check if the seals, heating elements, mechanical seal cooling water, and gearbox oil level are normal.
Sample pretreatment: Dissolve the mixture to be separated in a solvent and filter impurities to ensure material fluidity and compatibility with operating temperature.
Add materials: Slowly add the raw materials into the distillation kettle, controlling the amount at 1/3-2/3 of the volume, to avoid overflow or insufficient amount affecting the effect.
Start and Run:
Turn on the cooling system: Start the condensate circulation first to ensure that the condenser temperature is controllable (to prevent steam backflow).
Start the vacuum system: Start the vacuum pump group in sequence, pump to the target vacuum degree (experimental level can reach below 0.1Pa), and monitor the vacuum stability in real time.
Heating and film formation: Start the scraper rotor (speed ≤ 400rpm) to form a uniform thin film on the inner wall of the distiller; The heater heats up to the set value (lower than the normal boiling point of the material).
Process monitoring:
Parameter adjustment: Real time monitoring of temperature, vacuum degree, and scraping speed, adjusting heating power and vacuum valve opening to optimize separation efficiency.
Anti boiling measures: Zeolite should be added or the scraping system should be activated before heating, and high-temperature addition of materials is prohibited.