Page 19 - 81Sulfonation-Sulfation Processing Technology for Anionic Surfactant Manufacture_opt

286 Advances in Chemical Engineering

et al., 2005), and amount sulfur trioxide in the gas phase (SO 3/N 2), finally the temperature
of the process. This mathematical model permits to calculate the profiles of interfacial
liquid temperature, liquid film density, liquid viscosity for any column height and
longitudinal profiles of conversion. The proposed model may be suitable for use in design
and operation of industrial film reactors. To ensure convergence of the system of
equations then transformation of the equations proposed by Agrawal & Peckover (1980)
was chosen following the same development by Talens (1999). The set of equations
resulting from the mass, momentum and heat transfer is solved numerically. Figure 20
shows schematic view from the top of a reactor: the liquid is evenly distributed around
the wall, and the gas mixture is injected through the center of the column. The interfacial
temperature is affected by the SO 3 amount in the gas mix. It is clear an increase of
interface temperature result of the SO 3 excess in the gas flow. The temperature of the
reagents is a key control variable to avoid undesirable side impact that damage the
product mainly by strong coloration.

Fig. 20. An example of interfacial temperature profiles fall in the reactor longitudinal
Other example of the results provided by the model for longitudinal conversion profile from
top of the reactor (expressed as percentage of active matter) is shown in Figure 21(a). The
input values of the model are: SO 3/N 2 percentage at 5%, SO 3/methyl stearate mole ratio at
1; T G, T L, and T w at 343 K, 333 K and 313 K, respectively. This figure shows schematically the
fast conversion region at the top of the reactor (associated with gas phase control) and slow
conversion region at the bottom (linked with liquid phase control). The washing active
substance was determinate using a two titration technique with Hyamine 1622 as the titrant
reagent and methylene blue as indicator (Tsubochi et al., 1979; Milwdsky & Gabriel, 1982;

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