You may control when the packing calculations are performed and whether the column pressure profile is updated by selecting the desired calculation option.
Normally, tray hydraulics are calculated after the flowsheet calculations are complete. Select the During Column Convergence and do Not Update the Pressure Profile option when tray hydraulic results such as flooding factor, downcomer backup, etc. are referenced by other unit operations but it is not desired to update the column pressure profile using the calculated pressure drops.
Select the During Column Convergence and Update the Pressure Profile option when it is desired to update the column pressure profile to the calculated tray pressure drops and re-calculate the column with the new profile. The scaling factor may be used to ratio the calculated pressure drops from a theoretical tray basis to an "actual tray" basis. For example, if an overall tray efficiency of 80 percent is used to determine the number of theoretical trays in the model, a scaling factor of 0.80 is used to increase the calculated tray pressure drops to correspond to the number of actual trays in the column. You can enter the desired scale factor in the highlighted field, replacing the default value of 1.0. This is the default calculation method for packings.
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