DYNAMICS OF LINEAR INTERACTIONS IN HETEROGENEOUS MEDIA: A SYSTEMS APPROACH

Villermaux, J., 1990. Dynamics of linear interactions in heterogeneous media: a systems approach. In: M. Sardin and Schweich (Editors), Impact of Physico-Chemistry on the Study, Design and Optimization of Processes in Natural Porous Media. J. Pet. Sci. Eng., 4: 21-30. A general method is presented for modelling linear reversible interactions between a flowing fluid and a porous medium, taking into account non-ideal flow and mass transfer resistance. It is shown that the overall transfer function of the system may be obtained by combining the transfer function characterizing the flow pattern, and that characterizing interactions at the local level. Several mechanisms are considered : one single retention layer, several layers in series, several retention sites exchanging in parallel, diffusion into a porous solid. It is also possible to account for distributed exchange times and first order chemical reactions in both phases. Examples of simulations are presented. Deformation of the response to a pulse injection of tracer under the influence of mass transfer resistance, case of two sites of different activity exchanging in parallel, existence of a transfer time distribution. Different mechanisms may lead to identical shapes. Complex networks may be easily represented. Finally, simple hints are provided for interpreting peak shapes after the proposed models.