The effect of hydrodynamic multiplicity on liquid phase trickle flow axial dispersion

Residence time distributions (RTDs) were measured for trickle flow in a bed of glass beads at different liquid flow rates and hydrodynamic states to obtain liquid holdup and axial dispersion measurements using the piston-dispersion (PD) model. The different hydrodynamic states were achieved by means of different pre-wetting procedures. It was found that all dispersion data show the same relationship to interstitial velocity, independent of the employed pre-wetting procedure. This relationship strongly reminds of Aris–Taylor type dispersion found in laminar flow through tubes. Based on the analogy of laminar liquid flow through a set of parallel tubes, a theoretical relationship between partial wetting, dispersion and liquid flow rate can be determined. Wetting efficiencies calculated from this relationship agree reasonably well with existing correlations.