Problems in the experimental process of intermittent vacuum distillation separation
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Hello everyone. I am currently working on my graduation project, which involves using intermittent vacuum distillation to separate fragrances. During the experiment, steam fails to reach the top of the tower; the temperature at the top of the tower is very low, and no reflux liquid is generated. Meanwhile, the bottom of the tower is highly turbulent. After distilling for a long time, there is little change at all. What could be the reason for this? It is operating at the highest vacuum level; this has been the case for a week now, and it’s really confusing. I need help, thank you!
Perhaps the tower has poor insulation, and it is too tall.
I saw in the manual for the laboratory distillation column that the heating current can only be set between 0.2 and 0.3 A, with a column height of 1.2 m. It’s strange; once it was possible to steam it, but then it stopped working.
Vacuum distillation causes this phenomenon; you can try to analyze and rule out possible causes from these aspects. Is the vacuum level sufficient? Is the pot temperature sufficient? All that’s left is to check if there’s any leakage The most likely cause is probably the leakage of air.
Does the tower have a vacuum gauge? Check one by one; if the vacuum is fine, then check the tower insulation
There is a gauge on the vacuum system side, and the vacuum level is actually quite good. Because according to the equipment manual, the insulation current should be between 0.2 and 0.3A; I don’t dare increase it any further. I’m not sure if this could be the reason for the poor insulation.
Personal opinion. The following possibilities exist: 1. Insufficient energy supply ； 2. Is the distillation tower insulated? For insulation, heat loss may be high ； 3. Vacuum operation requires more energy compared to operation at atmospheric pressure.
Does that require more energy, meaning the heating power needs to be increased?
What was said upstairs makes sense as well; we need to consider the possibility of a leak in the system’s vacuum. If there is a temperature measuring instrument in the tower bottom, adjust the heating amount based on the separation temperature.
Check the vacuum level in the chiller; if there are no issues, then examine whether the insulation of the tower is adequate. If the insulation is poor, the reflux inside the tower should be high