variavel0=<b>Gilmar de Oliveira Veloso</b> - kriukov@main.unijui.tche.br UNIJUÍ
<b>Viktor Georgievich Krioukov</b> - kriukov@main.unijui.tche.br UNIJUÍ
<b>Horácio Antônio Vielmo</b> - vielmoh@mecanica..ufrgs.br UFRGS
<b>Abstract.</b> In this paper improves the mathematical model proposed in works previous of same authors, about the species extraction in countercurrent crossed flows. In the model, besides the phenomena considered previously (mass transfer between the phases pore and bulk, diffusion for the whole extraction field, influence of the shipment and drainage zones, existence of trays) is introduced: the species losses and its dispersion for the extraction field, the phase bulk drainage in last tray. Shipment submodel was modified. The mathematical model includes two evolutionary EDP´s and ordinary integral-differential equations, that are resolved by means of the method of lines. In the work was established the main conditions of calculation convergence and it was discussed the model and code validation. Are shown the specie concentration distributions of the stationary state for whole extraction field.
<b>Keywords.</b> Mathematical model, countercurrent crossed flow, oil extraction, porous media, method of lines.