Determination of the liquid level in the vacuum distillation column bottom
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Dear colleagues, I’ve encountered a problem while working with vacuum distillation recently. The bottom of the distillation column is drained using a water pump, and the operating pressure of the column is less than 10 kPa. The liquid level in the column bottom is determined based on the residence time; additionally, a higher skirt is required (meaning the skirt height should be at least 7–8 meters). Or should we simply set the liquid level higher?
Also, what are the operating conditions at the pump outlet? That’s also very important
Generally, the former approach is adopted, with a skirt base added, as there is also the requirement for the lowest installation height of the pump inlet.
Residence time is used to calculate the liquid level height, while NPSH is used to calculate the skirt height
How to set up a foundation that’s seven or eight meters long? Can’t we use a different pump, like a diaphragm pump?
It’s essentially water deoxygenation, and pumps are generally used for this purpose
Hello, I would like to ask you: when calculating the liquid level height, is it based on the discharge volume and a retention time of 5 to 15 minutes?
Generally, 5 to 15 minutes is sufficient; usually, raising the skirt level is considered to ensure the necessary net positive suction head, and it’s rare to increase the liquid level in the tower bottom – just my personal opinion!