Seeking guidance on bathtub trays
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Question: I’m just starting to work with tower equipment, and I don’t quite understand the gas-liquid contact in the bubble column shown in the diagram. In the downcomer on the right side of the diagram, the upper part contains the gas-entrained liquid; why is the lower part clear liquid? I can’t quite understand it; I hope those who are more knowledgeable can give me some guidance.
By \"clear liquid,\" he means that there are no bubbles in the solution. The solution flows by gravity from the upper tray to the lower tray; there is a level difference between the lower tray and the downcomer, so when the solution reaches the lower part, the bubbles should theoretically have already separated and risen upward.
Can I understand that the bubbles rise, and when the liquid flows to the lower part, the bubbles also rise to the upper part or escape through the liquid layer?
The bubbles in the clear liquid are carried down from the upper tray; the liquid flows through the downcomer (containing a certain amount of bubbles) and then reaches the next tray. The exact amount of bubbles present in the liquid, as well as the timing at which they can be separated, are determined through extensive theoretical calculations (related to membrane absorption and separation processes) as well as numerous experiments. Therefore, there’s no need for the original poster to worry too much about this issue.
The liquid on the upper trays falls through the downcomers carrying some bubbles; this separation process takes time, so there are specific requirements regarding the residence time of the liquid in the downcomers.
Hello, these are just my personal opinions, meant to be cross-verified with others’. The diagram you’re showing should represent a stripping tower. The principle of stripping involves heat exchange on the tray surfaces; the light components reach their saturation vapor pressure and thus vaporize. As a result, bubbles of light components form in the upper part of the downcomer, resulting in a gas-liquid mixture
Mm-hmm, I just saw this while reading and didn’t quite understand it, so I’m trying to find out more about it.