Prediction of breakthrough curves in packed beds: II. Experimental evidence for axial dispersion and intraparticle effects

The effects of axial fluids dispersion on breakthrough curves in packed beds is considered and formulae are derived for ‘F‐factors’, which allow heat transfer coefficients obtained by step testing to be corrected for axial fluids dispersion. A comparison of steady state and unsteady correlations for heat transfer in packed beds suggests that axial dispersion effects are incorporated in certain steady state heat transfer correlaions. Further correction would thus lead to errors in breakthrough curve prediction. Experimental data for breakthrough curves in packed beds of highly conductive and poorly conductive spheres is examined and Biot number correction factor 1 + Bi/5 shown to be valid for Biot numbers up to about 4.