Wall-Film Mass Transfer Coefficients of Fixed Beds

Abstract

In order to explore the film coefficient of a fluid adjacent to the inside wall of fixed beds, data were obtained on the rate of dissolution of β-naphthol, by passing water through the beds whose inside was coated with the same material.
Glass beads and sand were used as packings. The experimental range of the modified Reynolds number was from 1 to 2, 000, and the Schmidt number, from 1, 000 to 1, 700.
Table 1 presents the dimensions of the various solid particles and of tubes used in this work. Solution was analyzed by means of a spectrophotometer.
As the result, it was made clear that under the conditions employed in this investigation, the eddy diffusion in the radial direction had little effect on the coefficients of the wall-film transfer.
The experimental data and calculated results for typical runs are presented in Table 2.
Fig. 3 shows a summary of the wall-film coefficients, where Sh/Sc1/3 is plotted versus Rep.
In this plot the properties of the particles do not appear as a parameter. The following correlations are obtained from the lines drawn in Fig. 3.
Sh=0.60Sc^1/3Rep^1/2 Re_p<40
Sh=0.20Sc^1/3Re_p^0.8 Re_p>40