A. If sufficient residence time (around 8 seconds) is not provided to the downcoming liquid in
the downcomer, it may entrain some vapour
B. The liquid head in the downcomer should not be greater than one half the plate spacing to
avoid flooding
C. The discharge end of the downcomer must project far enough into the tray liquid so that no
gas bubbles can enter the open end and by pass the bubble caps
D. None of these