What problems can occur if the liquid flow rate in a plate tower is low?
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This post was last edited by zhxbkofkyo on 2016-3-4 at 15:04. As the title suggests, if the liquid flow rate in an absorption tower is very low, the weir coefficient is around 0.3; the absorption equilibrium calculations work fine, but what problems might arise from a hydraulic perspective? Are there any ways to improve it from the perspective of the tray structure? Can such a tower operate in practice?
At low flow rates, gas can carry liquid droplets, which may even lead to backmixing and reduce efficiency
Then, if I sacrifice some number of plates and increase the number of plates, can I ultimately meet the requirements? Since the client’s requirements are very strict – low concentrations are required in the gas phase and high concentrations in the liquid phase – only a small amount of pure absorbent can be used; below the middle section, however, a large flow rate can be used for circulation
Actually, I don’t know much about absorption towers either, and I’m not sure if what I think is correct. It seems that sacrificing the number of trays would be a solution with more disadvantages than advantages. However, when the flow rate is low, it might be possible to control foam entrainment by reducing the opening ratio, decreasing the diameter of those openings, maintaining a certain liquid layer thickness, and lowering the gas flow velocity. But in that case, the gas-liquid contact area might also decrease, so this issue needs to be considered comprehensively. Personally, I still think using the number of trays as a solution isn’t very good
For plate columns that are already in use, if the liquid flow rate is too low, it may lead to leakage or cause a deviation in the gas flow, thereby reducing the separation efficiency