During constant-pressure and constant-temperature dehydration, does an excessively high liquid level in the three towers be detrimental to the dehydration process?
Thread Content
As the title suggests: Dear teachers, I really don’t understand why, during constant pressure and temperature dehydration, high liquid levels in the three towers are detrimental to the dehydration process. Our master craftsman can’t explain why either. Do you know? Please tell me, young man. Thank you
High liquid level requires a long circulation time, resulting in poor dehydration effect
With a high liquid level and a large amount of oil, heat transfer is slow, so the dehydration effect is also slightly poorer.
The liquid level at the bottom of the tower is high, and the circulation volume is large. Not conducive to dehydration
Below the vaporization section at the bottom of each atmospheric and vacuum distillation column, there are four layers of trays known as the stripping section. If the liquid level is too high and occupies the space in the vaporization section, the trays in that stripping section cannot carry out the function of vapor-liquid exchange; as a result, water vapor cannot rise upward due to the oil layer with its high liquid level. For example, it takes time for a pot of boiling water to cool down on its own. If you use a spoon to lift the water from the pot and then pour it back in slowly, repeating this process several times, the heat is carried away by the steam as the water is poured in slowly, thus reducing the cooling time. Distillation works by preventing the oil from flowing directly to the bottom of the tower; instead, it allows the oil to vaporize fully as it moves toward the bottom, thereby enabling more heat to rise upward, and this rising heat in turn carries away more water molecules.
High liquid level, large circulation volume, slow heat transfer, incomplete dehydration, and time waste