DYNAMICS OF FIXED-BED REACTORS IN TERMS OF MASS DISPERSION

An important aspect of any design exercise is the reliability of the employed data. In the case of fixed-bed reactors, the inadequacies of the existing design information are now universally accepted. This contribution presents an attempt to elucidate the dynamic dispersive features of fixed beds by utilising a refined experimental approach together with a representative two-dimensional mathematical model of the physical system. Manipulation of the predictions in comparison with the observed data provided best estimates of the effective axial and radial dispersion coefficients for both the transient and steady-state situations. Empirical expressions have been established for the a priori determination of the dispersion terms. These are different from those predicted by the literature correlations with the discrepancy becoming greater with increasing values of Reynolds number. Values suitable for the transient case are found to be unsuitable for steady-state conditions. Interactive effects between the axial and radial dispersion factors have also been established.