False downcomer

Sieve trays installed with holes behind false downcomer. Entrained liquid overhead. Limited lean oil flow. Vessel manufacturer error. 

Arrangement b (often referred to as the false downcomer) is popular. It offers better liquid distribution than the others, does not suffer from hydraulic jump, and provides some flexibility in inlet nozzle orientation. The width of the false downcomer should be the same as the width at the bottom of a downcomer (307). For feed into center or off-center downcomers it is recommended to make the x -f- y dimension 12 in (307). If entrainment due to liquid splashing in the false downcomer is a concern, a horizontal baffle, with dimensions of about 2d by Wrf can be installed directly above the nozzle entry into the false downcomer. This baffle is installed at some clearance above the false downcomer. In most cases, there is no need for this baffle. 

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See also in sourсe #XX -- [ , ]

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