Tray efficiency criteria

The point efficiency is a fundamental criterion of mass transfer, whereas the overall tray efficiency is the value that can be measured, especially for larger distillation columns. Large-column... 

A reboiler may count as one 100 percent efficient separation stage only if it processes the total liquid from the bottom tray on a once-through basis, yielding boilup vapor and bottoms liquid. If this criterion is not met, take no tray credit for the reboiler. Observing rules 1 and 2 to reevaluate the number of stages required as tower trays, one now applies a tray efficiency which is nothing more than a judgment factor to obtain the number of actual trays to be specified for the tower. 

For packed columns, which are classified as counterflow columns (most trays are crossflow devices), mass transfer is related to transfer tassa in connterflow vapor-liquid cou(acting Hie most-used criterion of efficiency is the height equivalent to a theoretical plate (HETP) thet was first introduced by Peters 1... 

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