Correlation of liquid-side mass transfer coefficient for single particles and fixed beds.

Abstract

The mass transfer coefficients between particles and liquid were correlated for single particles and for fixed beds with specific power group including the energy dissipation rate defined for a particle. The following empirical equations were obtained over a wide range from laminar to turbulent flow, assembling the published data including those of the authors for fixed beds: for single particles Sh=2+0.59(ε1/3Dp4/3/v)0.57Sc1/3 2<(ε1/3Dp4/3/v)<63000, 570<Sc<1420 for fixed beds Sh=2+0.51(ε1/3Dp4/3/ν)0.60Sc1/3 0.2<(ε1/3Dp4/3/ν)<4600, 505<Sc<70600where e is energy dissipation rate per unit mass of liquid flowing around a particle, Dp is particle diameter, and ν is kinematic viscosity of liquid. These equations, almost identical, are also practically the same as published ones for stirred tanks, suspended bubble columns, and twophase tube-flow. The agreement suggests that specific power group may be useful as a general parameter in the study of mass-transfer phenomena between liquid and particles where the liquid is either quiescent or turbulent and the particles are either fixed or suspended.