Gas- and liquid-phase axial dispersion

Significant literature on the axiaj dispersion in gas and liquid phases for countercurrent-flow packed-bed columns have been reported. Trickle- and bubble-flow regimes have been considered. Unlike the holdup, there is quite a discrepancy in the results of various investigators. Almost all the RTD data are correlated by a single-parameter axial dispersion model. A summary of the reported axial dispersion studies in countercurrent flow through a packed bed is given in Table 8-1. 

DeMaria and White13 correlated their RTD data by the axial dispersion model. The axial dispersion coefficient was correlated by the relation 

Investigator Packing Column diameter (cm) Column length (cm) System 

Safer and Levenspiel45 1.27-cm Raschig rings I.27-cm Berl saddles 10.16 365.76 Air-waler 

Anderson et al.1 1.27-cm Raschig rings 30.48 91.44 Air - water, radial and axial dispersion 

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Recommendations As in the case of the holdup, all the data for gas- and liquid-phase axial dispersion coefficients have been obtained for packings normally used for absorption or gas-liquid reaction processes. These packings are large and... 

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