Empirical correlations for axial dispersion coefficient and Peclet number in fixed-bed columns

- The new axial dispersion coefficient correlation is more accurate than existing ones.
- The effects of mass transfer parameters on the new correlation are studied.
- The new correlation leads to lower Peclet number values.
- The new correlation considers both bed voidage and molecular diffusion.

In this work, a new correlation for the axial dispersion coefficient was obtained using experimental data in the literature for axial dispersion in fixed-bed columns packed with particles. The Chung and Wen correlation, the De Ligny correlation are two popular empirical correlations. However, the former lacks the molecular diffusion term and the latter does not consider bed voidage. The new axial dispersion coefficient correlation in this work was based on additional experimental data in the literature by considering both molecular diffusion and bed voidage. It is more comprehensive and accurate. The Peclet number correlation from the new axial dispersion coefficient correlation on the average leads to 12% lower Peclet number values compared to the values from the Chung and Wen correlation, and in many cases much smaller than those from the De Ligny correlation.