Individual Film Mass Transfer Coefficients in Packed Absorption Columns

Abstract

It is found that differences between the gas-film resistances in the evaporation of pure liquid and in the physical absorption reported by Surosky-Dodge and Houston-Walker are inversely proportional to the liquor rate and the former is corresponding to the latter at the infinite liquor rate. The gas-film coefficients thus obtained may be expressed by the equation,
Comparison of this equation and a few equations previously presented is shown in Fig. 7a, and it appears that the effect of the liquor rate on the gas-film coefficient is nearly the same order of the results of Whitney and Vivian.
Using the over-all coefficients for sulfur dioxide absorption obtained by Whitney-Vivian and the gas-film coefficients calculated from the above equation, the liquid-film coefficients are calculated and correlated as follows:
This liquid-film coefficients are 30-35% lower than those predicted from the Sherwood-Holloway equation over the range of the liquor rate usually encountered, and are slightly higher than those calculated from the van Krevelen-Hoftijzer and the Scheibel-Othmer equation as shown in Fig. 7b.
These equations derived here are yet far from the general applicability. They, however, are only applicable to 1″ Raschig ring packings over the range of 500-10, 000lb./sq.ft.hr of liquor rates and 100-600lb./sq.ft.hr. of gas rates. Figs. 6a and 6b show the comparison of the observed and calculated over-all coefficients.