Distillation - Downcomer Flood % Calculation
Distillation - Downcomer Flood % Calculation
(OP)
Can anyone tell me how "Downcomer Flood" can be manually easily calculated (for valve trays) based on both "backup flooding" approach and also "choke flooding" approach. I need to calculate it in percent form (however that is done) so I can compare it to a percent magnitude given by a supplier's rating sheet result. The supplier is unwilling to discuss how it is calcuated. Can anyone help.





RE: Distillation - Downcomer Flood % Calculation
Downcomer flooding is when liquid from the tray below backs up to the tray above. For backup flooding this is because the pressure drop across the tray is greater than the liquid head available from the tray spacing. The formulas to calculate pressure drop area readily available in Distillation Design by Henry Kister, Perry ChemE Handbook, and Unit Operation of ChemE by McCabe, Smith, & Harriott among others. You shouldn't have any problems calculating this on your own and it will be an empowering experience.
Choke flood occurs when there is insufficient time for the liquid to dearate. Downcomer residence time preferrably should be at least 5 s, more for foaming systems. This is any easy calc. and you should be able to determine if this is your problem.
Good luck.
RE: Distillation - Downcomer Flood % Calculation
RE: Distillation - Downcomer Flood % Calculation