Page 21 - 81Sulfonation-Sulfation Processing Technology for Anionic Surfactant Manufacture_opt

288 Advances in Chemical Engineering

The model was constructed to predict the sharp increase in the conversion that takes place
in the first stage inside of the falling film reactor. It confirms that the mass transfer is
initially controlled by the resistance in the gas phase. After due to several factors the
resistance occurs in the liquid phase. Figure 21(a) presents the conversion profile in the film
reactor from the model, experimental results showed conversions lower than those
predicted by the reactor model in upper reactor region. This is due that the model assumes a
fully developed flow and entrance effects of the streams to the reactor are neglected.
However, the model is able to predict adequately conversions downstream for longer
lengths. In the bottom of reactor is a small jump in the conversion predicted by the model,
perhaps due to kinetic effects that reach importance by the consumption of reactants.

Fig. 21. (a) Longitudinal conversion profile for SME and (b) density and viscosity model
estimated by the model

The most important outlet data obtained by solving the mathematical model are conversion,
density and viscosity of the product. The density and viscosity of the effluent, downstream
in the reactor film, estimated by the mathematical model is similar to that obtained
experimentally, as shown in the Figure 21(b). The increase of temperature produces a
decrease in viscosity enhancing the solubility of SO 3 in the liquid, and causing a decrease in
film thickness. These variations are the result of abrupt change in composition and release of
heat in the initial part of the reactor, which produce an increasing of the temperature in this

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