Real Stage vs. Ideal Stage for Columns

Lili Lyddon

November 28, 2006

Although you can model any column (for example an amine absorber) using real stages, ideal stages are recommended because the column executes much faster and calculations are much more stable. If you are designing an amine unit, you should ALWAYS use ideal stages in the absorbers and strippers rather than real stages. If necessary, a real stage model based upon the ideal stage design can be set up later. The use of real stages is not recommended except for matching plant operating data or an ideal stage simulation. Murphree and Thermal Efficiencies are used to modify the temperature profiles for cases with large temperature changes between stages, to match plant data, or give improved temperature profiles. Keep in mind that the use of Murphree efficiencies is not a predictive method but rather a tool for matching plant data (or calculations from another model such as ideal stages).

Authored by Lili Lyddon - BR&E Technical Support / Help Author