| Summary: | 博士 === 國立臺灣大學 === 化學工程研究所 === 81 === The absorption of sulfur dioxide into water drops is of great
importance in atmospherical scavenging and flue gas
desulfurization process. In the persent study，the data
reported in the literature were used to study the relation
between the liquid-phase mass- transfer coefficient and drop
diameter and proposed a semiempirical equation which is based
on the surface stretch model to correlate the experimental data
available. It was found that for the prediction of liquid-phase
mass-transfer coefficients for drops in the size range 0.06 to
0.6 cm dia., a semiempirical equation which is based on the
surface stretch model and mutiple a correction factor 0.78 can
best represents the experimemtal data. The experimental data of
Walcek et al.(1981) can be well described by ignoring the
effect of internal circulation and considering the diffusion of
both physical dissolved sulfur dioxide and HSO3- into the drop
interior and the equilibrium chemical reaction between them.
Liquid-phase mass transfer was found to be rate-controlling.
An analytical solution of the model was obtained by assuming an
equal diffusivity for all sulfur species. The results of this
study indicates that under experimental conditions of Walcek et
al., the internal circulation may not be important. The
absorption of SO2 by water drops was simulatd by a mathematical
model. The factors considered in this model are gas phase SO2
concentration, drop size, chemical reaction and internal
circulation. As the gas phase SO2 concentration increases, the
mass transfer rate increases. When the drop size is small, the
mass transfer rate is high and soon reach the saturated
concentration. The rate of chemical absorption is greater than
that of physical absoprtion. The effect of internal circualtion
on absorption increases with increasing drop size, however, the
neglect of the internal circulation results in a less than 10%
reduction of absorption rate.
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