Dominique Depeyre

An estimation of the film-penetration model parameters

Abstract It it shown in this paper that the process of evaporation of liquids into a turbulent gas flow in a wetted-wall column can be represented by the film-penetration model. The numerical values of the two parameters S and L of this model, estimated from mass transfer data, appear to be well defined functions of flow conditions. The surface renewal mechanism used in the considered mass transfer model was shown to be consistent with the momentum transfer concept. The results may be used to predict mass transfer processes with chemical reactions in similar flow systems, by applying the theoretical developments using the film-penetration theory [7–10]. The same procedure may be used to estimate the film-penetration parameters in other flow systems, such as the flow of liquid films in a wetted-wall column, or other complicated system such as stirred tanks, bubble columns, packed columns etc.

Pyrolysis of hydrocarbon mixtures characteristic of coal: Application to dibenzyl mixture

Abstract Thermal cracking of dibenzyl dissolved in two solvents, tetralin and decalin, has been studied in a flow reactor, in the presence of steam, under atmospheric pressure and at temperatures between 600 and 750 °C. The nature of the products obtained depends upon the structure of the hydrogen-donor agent, but is independent of the structure of dibenzyl. Valuable products such as ethylene and a benzene, toluene and xylene (BTX) mixture, obtained by a β-scission reaction with a monomolecular mechanism, are predominant when decalin is used as solvent. The dehydrogenation of tetralin to naphthalene precedes cracking reactions of the bimolecular type, which lead to significant production of hydroaromatics such as indene. Cracking of dibenzyl, followed by hydrogen transfer from the solvent to the radicals formed, leads to toluene irrespective of the chemical nature of the hydrogen donor.