Page 22 - 81Sulfonation-Sulfation Processing Technology for Anionic Surfactant Manufacture_opt

Sulfonation/Sulfation Processing Technology for Anionic Surfactant Manufacture 289

area. Same phenomena occur with the film thickness. The jump in conversion takes place in
the top reactor, the temperature rises considerably and reduces the viscosity of the liquid,
even canceling the effect of viscosity then in the bottom reactor increases composition and
the interfacial velocity. Subsequently, the reduced generation heat and descent of the
temperature is increase the viscosity again.

7. Conclusions
Transfer rates in the gas phase are affected by changes in the tubular reactor. Increases
uncontrolled in the gas flow could drag some liquid into the gas phase. Therefore the gas
velocity has to be set at the point where no liquid drops can be pulled to the gas phase.
Temperature is a critical parameter in the quality control of the sulfonated products.
Although inlet streams’ temperature should be adjusted above room to enhance the reaction
and avoid the solidification of the organic matter, an adequate control is required due to the
high release of heat attributed to the sulfonation reaction. The SO 3/organic liquid mole ratio
requires rigorous control. Excess of SO 3 enhance side reactions and extended reaction times
will also enhance side reactions.
The comparison obtained for this same process with petrochemicals compounds indicates
that the model could be applied to any film sulfonation but adjusting the parameters and
specific conditions, such as the physicochemical properties of the compounds used, since the
sulfonation process described in this work is one of the more complicated cases. Although
some of the physical and chemical properties of mixture are obtained of a similar form,
these should be tested and approach to achieve convergence of the model; these yielded the
best results in the mathematical model of falling film reactor.
The model predicts two distinct transfer areas. The first is characterized by an abrupt
increase in conversion and temperature, in which the controlling step depends initially of
the gas phase and in accordance with the extent of the sulfonation reaction, the viscosity
fluid increases, the film thickness is also higher and the film velocity decreases, then the
liquid phase becomes the controlling stage with a mild increase of the temperature and
conversion. The mathematical model proposed for a film SO 3-sulfonation fits adequately the
trend of experimental results, so it is now possible to make a prediction on the conversion in
a falling film reactor, because the profiles of temperature, density, viscosity and conversion
are consistent with experimental results that satisfy the conditions to minimize the strictest
mathematical calculations mistakes due to the usage of numerical solutions.

8. Notation
A pre-exponential factor, s -1
A + a van Driest constant
B + a van Driest parameter
C concentration, kmol/m 3 ; van Driest constants
c heat capacity, J/(kmolK)
friction factor, dimensionless
C f
D diffusivity, m 2 /s
d reactor diameter, m
 1.66   / w 1  
f damping factor, f  e
g acceleration due to gravity, m/s 2

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