Kremser group method

An alternative method for the design of an absorption or stripping column is based on the modular group method (Kremser equation, 12.33), primarily for dilute mixtures. The required number of stages for a specified separation is first determined. Once this is known, the packing height can be estimated from the relation... 

Under these conditions, the extraction factor Ee = Kp EIR or E = Dfi/R is also constant, and the Kremser [66] group method applies ... 

The Kremser approximation gives product distributions that deviate considerably from the exact solution, but the Edmister group method is in reasonably good agreement with the exact results. However, terminal stage temperatures of T, = 100.4°F (38.0°C) and Te = 163.3°F (72.9°C) predicted by the Edmister group method are in poor agreement with values of T = 150.8°F (66.0°C) and Tt = 143.7 (62.1 C) from an exact solution. 

Kremser originated the group method. He derived overall species material balances for a multistage countercurrent absorber. Subsequent articles by Souders and Brown, Horton and Franklin, and Edmister improved the method. The treatment presented here is similar to that of Edmister for general application to vapor-liquid separation operations. Another treatment by Smith and Brinkley emphasizes liquid-liquid separations. 

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