The plate efficiency issue in Aspen tower design
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Plate efficiency is divided into overall tower efficiency and individual plate efficiency, and the two are different. The plate efficiency is commonly used in the study of trays, while the overall plate efficiency is often used in tower design. In the ASPEN design calculations for distillation columns, when dealing with tray efficiency, the entire column is usually divided into a tray section and a condenser/reboiler section, and the efficiencies of these three sections are provided separately. In Aspen’s extraction column modules, it seems that it is not possible to provide the efficiency for the entire column; only the efficiency of each tray can be given. So how do engineers deal with this in their designs? Is it as simple as just performing calculations for the theoretical plates and then dividing by the overall column efficiency to obtain the actual number of plates? Can it be set directly in Aspen?
Why isn’t there anyone answering this? Looking forward to answers from experts
It is recommended that fellow sailors not devote too much effort to theoretical research on board efficiency. To achieve the same separation effect, different thermodynamic models yield different numbers of theoretical plates; moreover, the actual number of plates required in practice to attain a certain separation effect is fixed, which means that the plate efficiency varies among different thermodynamic models. I have actually obtained a plate efficiency of 150% for a certain thermodynamic model by comparing it with theory
Plate efficiency is indeed a weak point in the design; of course, it would be best to have reference data from similar systems, but if that’s not available, some formulas can be used for calculation. Commonly used ones include the Maxwell correlation and the O’Connell correlation. If Maxwell’s correlation equations are used, it is indeed possible to have the plate efficiency exceeding 100%, as mentioned above.
What is simulated is a theoretical number of plates; the tower internals manufacturer only guarantees the hydraulic performance. If efficiency is not taken into account and the number of trays is not fixed, how can quotation requests be sent to various manufacturers? I’m a bit confused
It seems this problem continues to plague a large number of people······