Sieve-plate columns normal operation

NORMAL OPERATION OF SIEVE PLATE. A sieve plate is designed to bring a rising stream of vapor into intimate contact with a descending stream of liquid. The liquid flows across the plate and passes over a weir to a downcomer leading to the plate below. The flow pattern on each plate is therefore crossflow rather than countercurrent flow, but the column as a whole is still considered to have countercurrent flow of liquid and vapor. The fact that there is crossflow of liquid on the plate is important in analyzing the hydraulic behavior of the column and in predicting the plate efficiency. 

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