Hydrodynamisches Verhalten und Stoffübergang an Siebböden im Sprudel‐ und Sprühbereich

Abstract

AbstractHydrodynamic and mass transfer behaviour of sieve plates in the spray and bubble regimes. An attempt is made to set up idealized hydrodynamic models for the bubble and spray regimes on sieve plates and thus to provide a basis for calculation of mass transfer and concentration ratio. Comparison of the dependence of plate efficiency in the two regimes on various parameters indicates the importance of being able to determine a practical phase transition point. This was defined on the basis of the contribution of the bubbles and droplets to the overall interfacial area and compared with the transition points of other authors. The operation of columns in the spray regime, formerly regarded as undesirable, now possesses considerable industrial significance. This was mentioned by Zuiderweg [29] in his Underwood lecture of 1973. Since that time larger perforations and higher gas velocities have been employed. There has consequently been a significant shift of sieve plate behaviour from the bubble to the spray regime. It is estimated that almost 80% of all industrial sieve plate columns now operate in the spray regime and should be specifically designed for such operation.